


As Our Feet Find the Sand

by Eugara



Category: Supernatural
Genre: Bottom Dean, Established Relationship, M/M, Merpeople, Top Sam, Transformation
Language: English
Status: Completed
Published: 2014-10-04
Updated: 2014-10-04
Packaged: 2018-02-19 19:59:06
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 27,713
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2401052
Author URL: https://archiveofourown.org/users/Eugara/pseuds/Eugara
Summary: <blockquote class="userstuff">
              <p>Season 6.  The last thing Dean is expecting to see during a basic hunt in Maine is an honest-to-god merman.  But when that becomes the least weird thing he and Sam have to deal with on the whole case—well, that’s when Dean knows he’s fucked.  Because no matter how much his brother promised to help the guy out, tails of their own were not part of the plan.</p>
            </blockquote>





	As Our Feet Find the Sand

“There is absolutely no way that dude is coming back.” Dean digs the toe of his boot into the wet sand underneath him and lets the saltwater seep in from below until he’s created a little well. Then he sighs and scuffs the whole thing out with his heavy sole. “C’mon, Sammy. You know the guy booked it the instant we let him go.” Dean peers out across the dark, unending swell of the ocean—like he could see a retreating silhouette if he tried hard enough—and grumbles, “He’s probably halfway to Honduras by now and we’re never gonna see him again and that bronze net was a total waste of what little money we _didn’t_ have.” He shoves his freezing fingers underneath his armpits and glares out at the sea, more sullen about the oppressive chill in the night air than their prisoner’s pseudo-escape.

“Not my fault your ‘net guy’ only accepted cash,” Sam says matter-of-factly, completely unbothered by the icy sea breeze. “Skeevy guys who operate out of busted-up vans are not the most reliable source for magical weaponry.”

Dean just snorts in response, bouncing on his toes to try and get his circulation pumping. “Did you ever think that you’d actually get to the point where you’d miss Bela?”

His brother grants him a polite laugh and sweeps some of his wind-tousled hair away from his face. “Yeah,” he says sarcastically. “She’d only have made us grab her some irreplaceable artifact in exchange. And then she’d have robbed us blind while our backs were turned.” Sam rubs at the corner of his mouth. “Actually, she’d probably have taken the shirts off our backs _too_.”

Dean feels a small smile tug at his lips as he stares out across the pale stretch of sand before them. “Could you imagine what we could buy with all the shit from Campbell’s library?” Sam makes a disapproving noise, and Dean grins for real. “I’m serious, man. She probably would’ve forked up a couple mil for just a _few_ of the books wedged down under Samuel’s office.” He lifts a persuasive eyebrow. “Whaddya think, Sammy? We could retire rich, head down to the Keys, work on our tans.” Dean suppresses a full-body shiver and pulls his arms in tighter. “Y’know, somewhere where the beaches are _warm_ like they’re freaking supposed to be.”

“That hypothetical universe you live in sure sounds nice,” Sam says dryly. He turns to fix Dean with a look, and then his eyes widen as he takes in his obvious misery. “Shit, dude.” He tries—and fails—to suppress a laugh, stepping up behind Dean to rub at his arms. “Are you really that cold? Why didn’t you say something?”

“I _did_ say something,” Dean mutters grumpily, but he lets his brother manhandle him with his ginormous paws. “I said, ‘This beach is fucking cold.’ And then I said, ‘Why do we have to go on a goddamn mermaid hunt in the middle of the rainy season?’ And then _you_ said, and I quote:” He puts on his best whiny Sam-voice. “‘ _Because._ ’”

“I don’t sound like that,” Sam protests tepidly, but he seems to be more interested in making sure Dean doesn’t freeze to death than protecting his own dubious honor. He finally gives up on the rubbing and tugs Dean down onto the damp sand instead, ignoring his very manly complaints about being cuddled in order to scoot up behind him. His brother wraps surprisingly toasty arms over Dean’s chest and then hooks his chin over his shoulder. “Dude, you can stop with the whining already. I’m not gonna let you get pneumonia just because you’re an idiot.” Sam grins against the side of his neck, way too amused at his suffering. “You should have just worn your jacket.”

“It’s _June_ , Sam,” Dean gripes. “What’s the point of even _having_ a beach in Maine when it just rains all the damn time?” Sam doesn’t say anything in reply, but his legs come up to cage Dean’s own—a long stretch of warmth on either side. Dean makes a brief, half-hearted attempt to resist succumbing, but there’s really no way that he can stop himself from melting back into Sam’s sinfully delicious body heat, despite his earlier grumblings. So he resigns himself to shifting around until he’s decently comfortable in his brother’s arms, and then gives up, glancing back out at the water as he thinks over their last few days. 

They’d heard about tourists disappearing off the rocky coast while still skulking around Bobby’s house. All three of them had been up to their eyeballs in the search for Crowley’s possibly-alive-this-whole-time hideout after the Eve debacle in Oregon, but Bobby had kicked them out the door the instant an excuse came up, muttering something about them “giving him a headache” and him “working better alone anyways.”

So they’d packed their shit and hauled ass to Maine quick as they could. Sam thought it was a misplaced kelpie doing the snatching, Dean had been certain it was a phantom attacker, but they’d both been struck dumb when they’d first seen the unmistakable flip of a tail directly off the shoreline—way too shallow for sharks or any of the larger species of fish. Gino had been the only contact that Dean had this far northeast, so they’d doubled down on every bit of bronze the guy had stocked in his creepy van, and headed back to stake out the secluded beach. It had only taken all fucking night before their perp had finally gotten himself tangled up in their net, and Dean’s still trying to wrap his head around what he had seen with his own two eyes. Because the dude was a friggin’ real-life mermaid. Sorry—mer _man_. Dean rests the side of his head against his brother’s and tries not to make the obligatory Zoolander joke.

He hadn’t looked like one of those adorable Disney cartoons either. More like a deep-sea junkie than a cute little redhead in a shell bra. The guy had scraggly blond hair, but it was shot through with sickly green, like he’d been swimming in chlorine for way too long. Really, it had looked more like a tangled, ratted mop of seaweed than anything else. And he’d been thin. _Scary_ thin. Bones straining against the skin of his joints thin.

The merman had looked up at them with big (too big, _creepy_ big) gray eyes and fed them some bullshit story about being a victim just like the others. He had insisted that something else was snatching the out-of-towners for a midnight snack, and that it was driving all the food away from the rest of his mermaid pals too. “We don’t hurt humans, man,” he had blubbered. “Just fish, man, I swear. It’s something else. I’m just trying to stop it too.” He’d begged for their help hunting down the imaginary monster and Sam had bought the whole thing. Hook, line, and sinker.  _Ha_. Fish puns. So basically, his annoyingly gullible little brother had let the guy go to “fetch something that could really help, I swear, man.” And now, here they are—bored and useless and cold.

Dean takes a deep breath of the salty air, then nudges his brother with his shoulder. “Hey,” he says. “Bet you big money that mermaid Cobain isn’t coming back.”

Sam smiles against the side of his neck and lightly drags his lips over Dean’s pulse point. “Really, Dean? You seriously wanna put a wager on it?”

“Oh, abso-fucking-lutely.” Dean leans back into Sam’s hold and sucks at his teeth as he muses over possible terms for the bet. “If the guy’s gone for good and I win,” he says melodramatically, “then…you have to go to that Jethro Tull concert with me next month.  _And_ —” he raises a finger, “you aren’t allowed to say a single shitty thing the whole time.” 

Sam makes a horrible groaning noise and tucks his face into Dean’s nape, away from the wind. “C’mon, man,” he whines. “I went to that Metallica thing last February. Isn’t that enough?”

“Sorry, Sammy. Them’s the stakes,” Dean taunts childishly. “But hey, if it’s too rich for your blood, I get it.” 

“Oh, shut up.” Sam snuggles closer in against Dean’s back, then makes another unpleasant noise deep in his throat. “God, he’s so dumb. He makes his people dress up like giant rabbits and shit. Why do you even like him? It’s like if Yo Gabba Gabba grew up and started doing hard drugs.” 

Dean relaxes into a grin his brother can’t see, knowing that he’s already won the battle. “Obviously you just don’t understand the intricacies of progressive rock.” 

“No,” Sam agrees easily, butting his head into Dean’s shoulder blade. “No, I do not.” He takes a deep breath, then lets it out in a long, drawn-out sigh, finally giving in. “Fine,” he says grudgingly. “What do I get if _I_ win?”

Dean shrugs and nudges his hands under the warmer ones resting on his chest, letting them sit there. “I dunno. Blowjobs for a week? What do you want?”

His brother goes quiet for a moment, thumbs rubbing over Dean’s knuckles as he thinks about it. Then, after a short while, he huffs out a laugh. “How about this?” Sam asks, leisurely stretching up to whisper sin into the shell of Dean’s ear. “If I win,” he starts, thick and sweet like honey, “…then you have to _ride_ me.”

“Dude, what? No way.” He jerks away from Sam—not completely dislodging himself, but far enough that he can make out the side of his brother’s face. “No way in _hell_ am I bouncing on your dick like some drunk chick at a country-western bar.”

“What? Why not?” Sam twitches behind him, all whiny and shit. “I do it for you all the time,” he complains. “Why do you even care so much?” Then Sam lets out a sharp huff against the side of Dean’s face and says, “No, wait. Let me save you the trouble.” He clears his throat and pitches his voice low, like he’s gargling glass. “‘Blah, blah, blah, Sam’s a girl, blah.’ That sound about right?”

“Well, you’re the one who said it,” Dean mutters. He shifts around awkwardly and sighs. “Look, just pick something else, okay? How about I take you to a petting zoo or something? You like those.”

Sam hums nonchalantly, the picture of perfect disinterest. “Sorry, Dean,” he parrots back at him obnoxiously. “Them’s the stakes.” Then he leans back like he’s totally willing to let the whole thing go as long as he doesn’t have to tag along to any concerts. “But hey, if it’s too rich for your blood I totally—”

“Oh my god, fuck you. Fine. It’s a fucking deal.” Dean thumps his head back against his brother’s shoulder and glares up at the overcast sky. “Doesn’t even matter. There’s no way Filet O’Fish is getting within five hundred feet of us. You’re gonna come with me to that concert, and then you’re gonna blow me in one of the janky-ass bathroom stalls.” He can feel, more than hear, Sam’s laughter at his back. “And you’re not allowed to complain,” he reiterates. “Not even once.”

Sam’s bulk is already shielding Dean from the worst of the cutting breeze, but he shifts even closer around him at the ultimatum. “Deal,” he says warmly.

“Aw, that’s nice,” a sincere voice calls out from the edge of one of the rocky outcroppings.

Dean violently yanks away from Sam’s hold at the unexpected company and scrambles to his feet. “What the fuck, dude?” he yells. “How long have you been sitting there?”

“Oh, no worries, man. I was just watching the moment.” The merman from before glides out from around the jetty and gives them a half-lidded grin, his ratty hair dragging through the water behind him. “You guys are sweet.”

Dean can feel his eye start to twitch and he turns away to try and get a hold of himself, letting his brother take over before he goes fully apoplectic. “You came back,” Sam says, clearly perplexed. And then Dean has to take another few deep breaths before he explodes over losing the bet as well.

“Yeah, man. I told you I would,” the merman says. Completely guileless, like he has no concept of why Sam could possibly think otherwise. “You guys said you were gonna help me out, right?”

“Uh…right,” Sam replies. “Yeah.”

Dean turns back just in time to catch his brother’s unsure glance. “And what exactly _is_ it that you had in mind?” Dean calls out across the beach.

“Oh, right.” The merman fumbles for a bit below the surface, then pulls his arms back up above the water, triumphantly clutching some kind of cord in either hand. “Ta-dah, man,” he proclaims, incongruently mellow. “Now you guys can help.”

Dean takes a few steps down the shoreline until he can pull the whatever-they-are out of the overgrown guppy’s grip. He lifts the two strings up against the hazy moonlight until he can make out the vague shape of both objects. “Wow,” Dean says dryly. “Jewelry. How helpful.” 

They’re necklaces, both identical, and they look like they’ve been made out of anything the guy could scrape together from the ocean floor. The cords are plain twine, and each one holds a small, white seashell at the end where a charm would usually be.

Sam steps up beside him to snag one of the strands, then fiddles with the curled shell knotted at the bottom. “How are these supposed to let us help you?” he asks, tilting his hand back and forth so the shell glints brightly under the moonlight.

“Oh, whoops. Yeah.” The merman lets out a low-key chuckle. “Sorry, man, forgot to tell you.” He lifts his hands up and holds them out dramatically, like he’s waiting for a drum roll. “They totally let you breathe underwater, dude.”

Sam’s brows draw down. “Seriously?”

Dean, however, remains skeptical. “These don’t really look like legit hoodoo,” he says. Then tosses out a reluctant, “No offense.”

“Nah, man. I swear it’s good.” The merman leans back until he’s floating flat along the ocean’s surface, not looking insulted in the slightest. “Primo magic, dude. Cream of the crop.” He drifts up with the swell of a wave, then lets it carry him back down. “Super potent stuff. Promise.” He lets out another rambling laugh, then says, “Cross my heart and junk.”

“And why do we need to breathe underwater?” Dean asks warily.

“That’s where the guy is, man. The one who’s taking all your human buddies.” The merman nods solemnly. “I know, like, exactly where he is. But I just don’t wanna go in there by myself. You feel?”

Sam snorts quietly. “Yeah, Dean. You feel?”

“I _will_ hit you,” Dean shoots back at his brother under his breath.

They both hesitate for a beat, and then Sam shrugs at him and tugs the cord over his head, letting the shell thump down against his breastbone. They stare at each other for a second, but the jewelry doesn’t appear to be having any ill-effects. So Dean guesses that worst comes to absolute worst, they probably just don’t do anything at all, which really isn’t _that_ bad in the grand scheme of things. He fiddles with the empty nautilus husk for another few seconds, then sighs and pulls his on as well. It sits right where his amulet used to and Dean ignores the sick twinge of remorse that flares up in his gut. He clenches his jaw and pushes the memory aside—if he doesn’t think about it, then he can’t feel guilty.

Sam turns back to the now upright-again merman. “So…we can seriously breathe underwater now?” he asks dubiously. He scratches at the twine with a fingernail for another moment, then frowns. “Do we just walk in?”

“Uh, sure, man.” The merman drifts back a little bit from the shore’s edge. “But you might wanna…” He chews at his lip a little nervously. “Uh, I mean, don’t worry about it. You’re good. But… You might wanna wait just a bit.”

Dean tilts his head closer to his brother’s and murmurs, “I’d make some sort of seaweed joke, but I think it might be _too_ easy.” He sniffs contemplatively. “Which is actually a first for me, surprisingly enough.” He glances at Sam, but his brother doesn’t seem to be paying any attention to what Dean’s saying, so he snaps his fingers in the few inches of space between them. “Hey. Sam. You’re missing some prime-time hilarity here.”

Sam winces and brings a hand up to his ribs. “Yeah, sorry,” he says distractedly. “It’s just…” His brow furrows and he curls his arm around his torso, still not meeting his gaze.

Dean pauses. “Sammy,” he says cautiously. “You okay?” 

“Yeah. I’m fine.” Sam frowns absently as he rubs at his side. “It’s nothing. It just kinda feels like—” He lets out a tiny, hitched breath, and then a harsh cry suddenly rips its way out of his throat as he drops like a lead weight onto the packed sand below.

Dean’s Colt is out of his jeans and leveled at the merman’s head before he can even give his arm the command to move. “What the _fuck_ did you just do to him?!” he shouts. A slow, stinging sensation prickles up along the edge of his ribs, but he ignores it in favor of keeping a bead on the asshole floating in the water. “Answer me!”

The merman immediately throws his arms up in the air, showering himself and Dean with freezing droplets. “It’s nothing, man! S’all good. It’s what’s supposed to happen.” He cowers back from the muzzle of Dean’s gun. “He’s fine, I swear. Please don’t shoot.”

Dean struggles with his next move for one agonizing moment, before shoving his gun away so he can lean over his brother. He wraps his fingers around the shell hanging from Sam’s neck and pulls, but it’s stuck tight, held fast with whatever magic is working its mojo on him. “Sam,” he barks. “Talk to me, man. Are you okay?” His brother just lets out a pained groan and digs his head back into the sand, clenching his eyes against whatever’s happening to him. “C’mon, buddy. You’ve gotta work with me here.” Dean trails his hands over Sam’s sides, and they feel different somehow, but he can’t quite put a finger on why. “What’s hurting?” Sam doesn’t answer, so he pulls back to try and gauge the situation himself—and then Dean’s entire lower body seizes up like he’s on fire and he pitches forward onto his brother’s chest, legs suddenly buckling underneath him.

The searing pain radiates out from the base of his spine, latching onto his hips and crawling down his legs until all of his muscles contract at once, rigid under the waves of coursing agony. Dean tries to struggle to his feet, but his knees won’t bend the right way—cramping up and fixed straight like he’s been struck by lightning. Little, stinging darts shoot up his sides and arms and neck, but the needle pricks aren’t anything compared to the intense shockwave below his waist. Dean curls himself tight around his brother’s rigid form, unable to do anything but ride out the constant pain.

Finally, after what feels like hours, the ache eventually starts to abate, fading down past his hips in the exact same way it had started. Dean gets his hands underneath him as soon as he’s able to breathe again and swallows around the unexpected soreness in his throat, like he’d been yelling himself hoarse without even realizing. He pushes himself up from where he’s still draped across Sam’s chest, and then his arms nearly buckle again the minute he gets sight of his brother stretched out beneath him.

Sam is…

He’s got a…

Jesus fucking Christ, his brother has a _tail_.

Sam’s eyes are pinned open and blown-out with shock, and he’s staring up at Dean with the exact same gawping expression he’s sure is pasted all over his own face. Sam swallows hard, and Dean follows the flex of his brother’s throat—because his brain is apparently too broken right now to handle looking anywhere else. But he’s Dean fucking Winchester, and no way is he gonna let some bizarre, Twilight Zone weirdness get the better of him, no matter the circumstances. Dean takes a deep breath, sets his jaw, and then slowly forces his gaze down over the rest of Sam’s body.

The giant fish tail is… _yeah_. It’s there. And very prominent and really freaking weird and bright red. It starts right at Sam’s hipbones, small, lustrous scales scattered up and across his lower abs before converging together into the densely-layered sheen that makes up the rest of his new appendage below the belt. The whole thing is solid red—and flat, like one of those giant tunas—before darkening to a deeper, speckled wine color at the base. And the— _Christ_ —the fucking _fin_ where Sam’s feet should be is a paler pink, flimsy and gossamer-thin. Sam’s jeans are shoved down into a damp, sandy heap below the base of the thing, and the entire tail twitches as his brother shifts up with a quiet whimper.

Sam’s mouth opens and closes a few times, like he can’t quite settle on what to say, and then he brings up a shaking hand to brush over the sudden addition to his anatomy. His hands look longer somehow. Thinner. And the natural webbing of his fingers has crept all the way up to the second knuckle, translucent and pink, just like the lower fins. A quick glance at Dean’s own hands, still curled into the plaid fabric where Sam’s shirt has ridden up, reveals that they match in everything but color. Which unfortunately means that there’s no way Dean got off scot-free in the _other_ department either. He takes a second to steel his nerves, and then glances down at himself.

And… Of course, he had to be right. Dean lets out a bitter sigh. _Awesome_. His own—god fucking dammit— _tail_ is a deep green, and the size and shape are roughly the same as his brother’s, but that’s where the similarities end. Unlike the solid color that Sam is sporting, Dean’s got a ton of large, irregular splotches mottled across the length of it. Brown and shiny bronze and even a darker green. Like one of those calico goldfish with the big eyes you can pick up for five bucks at any random pet store. His weird, sheer fins are a lighter sea-foam color and Dean would complain about the unfairly girly shade, but at least it’s better than Sam’s pink.

“What…the hell?” Dean grinds out darkly, finally finding his voice.

“I don’t know.” Sam stares at his newly webbed hand in terrified awe.

“No. _Seriously_. What the hell?”

“Dude. Dean. I don’t fucking—” He wiggles his fingers. “I don’t know, man. I mean—this is just… _Jesus_.”

“Hey guys,” a tremulous voice warbles out. “Told you everything would be cool.”

“Are you _kidding_ me?!” Dean twists around to yell furiously. “You couldn’t have given us a little _warning_ or something? What the fuck is wrong with you?”

“C’mon, man,” the merman says defensively. “I told you it would help you breathe underwater, and now you can. I totally told you the truth.”

Dean glares out across the water, wishing that he’d gotten laser eyes instead of the mostly useless fish parts. “This is _not_ ,” he snarls, “telling us the _truth_.”

“Dean,” Sam says quietly. But Dean shakes off his staying hand with a violent twitch of his shoulder.

“I’m sorry,” he sneers down at his brother. “Do you actually still want to _help_ this guy?”

Sam lets out a short sigh and chews at his bottom lip. “Dean, something’s out there and ganking civilians. This is probably our best chance to stop it, and you know it.”

“Yeah, man,” the merman chimes in agreement. “You should totally come help me out. So if you guys are ready to go, we can just—”

“ _Five minutes!”_ Dean roars. “Just give us five fucking minutes or I swear to god—”

The merman immediately flinches back from his violent screaming. “Of course, dude,” he squeaks. “Anything you need, man. Yeah, I’ll leave you guys alone. Back in five. Just like you said. Whatever’s good for you.” He ducks back around the corner, still spouting out faint reassurances until he disappears from view completely.

Sam nervously glances up at him and reaches out a hand, almost grazing his shirt before he hesitates and pulls back. “Dean, you okay?”

“Peachy,” he growls. He tries to shift himself back onto his knees (or whatever the hell his knee area _is_ right now), but he falters under the weight and Sam has to catch him by the shoulders before he falls face-first into his brother’s chest. Again. Sam immediately removes his hands as soon as Dean gets his bearings and innocently flicks his eyes everywhere and anywhere else, probably trying to avoid the vicious murder Dean’s sure is evident in his gaze. 

And as Sam swivels his eyes away from Dean’s own, the light hits them at a certain angle and they shine like an oil slick. Dean frowns and grabs at his brother’s chin, tilting it back toward him until he can figure out the reason. Sam’s eyes aren’t any bigger (or creepy-round like their mermaid pal’s), but there’s a strange, wet film spread over each one. And it keeps catching the moonlight in odd ways, like the shimmer on those weird, smooth earrings that Lisa had liked so much. The shiny ones that looked like a space rainbow inside.  _Opals_ , that’s it.

Dean leans in a little closer and Sam tries to pull back. “Dude, what are you doing?”

“Are my eyes weird? ‘Cause your eyes are weird.”

“I dunno,” Sam mumbles through the grip Dean’s got on his jaw. “What do you mean by ‘weird’?”

He shifts back as best he can and tips his head up to catch the light. “Like, are they all glowy and shit?”

“Jesus,” Sam whispers. “Yeah, they are.”

Dean lets out a harsh breath and drops his head back down. “So how many more surprises do you think this thing dropped on us?” he asks sourly.

Sam frowns suddenly and snaps a hand up to skate over his ribs. “Before,” he says distractedly, “I felt something…” Sam wriggles between where Dean’s arms are holding him steady, and tries to ruck his shirts up. Dean helps as best he can—only able to use the one hand if he doesn’t want to collapse on top of his brother—and between the two of them, they eventually manage to get Sam’s over shirt undone and his v-neck off. 

“Whoa,” Dean says as soon as he catches sight of his brother’s bare skin.

“What?” Sam scrunches his neck down to try and see for himself. “Is it bad?”

Sam’s nipples have quickly pebbled up in the chilled air, but Dean runs his free hand directly past them and over the now-hairless skin of Sam’s chest to fixate on the long, repeated slits on either side of his torso. “This is gonna sound nuts,” he says slowly. “But I think you’ve got gills, dude.” They’re raised all along Sam’s sides and Dean belatedly understands why his ribs had felt so strange earlier. Each gill is tilted out, tinged pink and venting with every one of Sam’s breaths, and the skin is slightly hardened at the tip of each one. Like cartilage. His brother shudders as Dean traces a gentle finger along one rim.

“No way,” Sam breathes. He lifts his head and rolls his shoulders back trying to get a decent look, then eventually gives up and reaches for Dean instead.

“Hey, c’mon,” Dean complains as Sam yanks his shirts up over his head. “Sam, quit it.” The cold air hits him hard, the instant he’s shirtless, and Sam gapes as he runs his eyes over Dean’s sides.

“Fuck me,” he whispers. “This is crazy.”

Something about Sam’s words, and the way he’s now reverently grazing his fingertips down Dean’s abdomen, hits him with a terrifying thought. “Hey, Sammy,” he says carefully. “You don’t think—?” He swallows as his brother glances up at him. “I mean, it’s not like I can see anything. But I’m not exactly sure how the whole thing works, so… Y’know?”

Sam gives him a look. “Dean, I have no idea what you’re asking me.”

Dean lets a sharp breath punch out of his lungs—which he’s assuming he still has considering he hasn’t keeled over yet—and meets his brother’s gaze head-on. “My dick, Sam,” he says bluntly. “Where the fuck is it?”

Sam blushes bright red, and if Dean weren’t so focused on being worried right now, he’d laugh at his brother’s ridiculous prudishness. “Um,” Sam mumbles. “I’m not exactly sure if…” He shifts a little. “I mean, it’s just… I don’t know if—”

Dean really doesn’t have time for the embarrassed stuttering, so he leans forward to crush his lips against his brother’s, lifting a hand to cradle Sam’s jaw and trying his best not to leave sand all over his face. Sam stiffens for a brief moment, but quickly melts into the kiss, tugging Dean closer and sighing into his mouth. And it’s nice. It is. But Dean can’t feel the answering buzz of lust that usually lights him up every time he’s got his hands on Sam’s bare skin, and it’s freaking him out. He makes one last solid effort, sucking at his brother’s lips and tracing his tongue teasingly along the seam before pulling back to catch Sam’s gaze.

“Anything?”

Sam blinks at him a little dreamily before his words register. “ _Oh_ , uh…” Then his head seems to clear a bit and he shrinks back in apprehension. “No,” he admits quietly. Painfully apologetic. “Not really.”

“Jesus fucking Christ,” Dean mutters under his breath.

“Fish don’t really— Uh, they _spawn_ , y’know? So it’s not like…”

“Sam,” he grits out between clenched teeth. “Shut up. I don’t want to hear it. I don’t want to know anything about it.” He digs his fingers back into the wet sand and lets the rough bite against his palms center him. “I’m going to pretend that this isn’t happening, and after we’ve done whatever we need to do, we are never mentioning this _ever_ again. Got it?”

“Hey. Look, Dean. It’s okay.” Sam splays a comforting hand over his chest, right on top of the nautilus shell. His fingers feel kind of weird and slimy against Dean’s bare skin and he does his best not to flinch away. “I’m sure we can just take these off after, and everything will go right back to normal.”

Dean curls an experimental hand around Sam’s necklace and lifts it away from his brother’s body. “Yeah,” he admits grudgingly. “At least it looks like they’re not stuck anymore.”

“Maybe they just don’t come off in the middle of the whole,” he flaps his hand around, “ _thing_. Y’know? Like a safety precaution or something.”

“We could just take them off right now,” Dean offers. More sincere than he probably should be considering lives are at stake. “Forget the whole thing and head back to the motel.”

Sam gives him a look. “We did agree to help,” he says.

“Yeah, well I meant on my own fucking legs,” Dean spits half-heartedly. “I was figuring more Roy Scheider, less Daryl Hannah.” He sighs and thanks their shitty luck that at least they’re mostly hidden by the large breakwaters on either side of the beach.

“I don’t know, man. It kinda makes sense, right?” Sam shrugs his shoulders, displacing the sand underneath him. “How else would we get around down there?”

“I can’t believe you’re okay with this.”

“Don’t get me wrong, dude. It’s freaking weird.” He lightly skims a fingernail over Dean’s gills to underscore his point, then stares up at him. “It’s just that, well, our whole _lives_ are freaking weird. Y’know?” Sam’s eyes catch something over Dean’s shoulder and he sighs prissily, letting his head thump back against the ground. “Plus, our friend is back.”

“Hey, dudes,” Dean’s least favorite person in the entire world calls out from behind them. “You all ready to go now? ‘Cause we should probably go help your human pals. Don’t you think?”

Dean sighs and gives up. “Fine,” he throws gruffly over his shoulder. “Yeah, we’re coming.”

“Right on, man,” the merman crows. And then Dean’s brain tries to slide out of his ears once he realizes that, technically, they’re _all_ mermen here.

Sam gives him a look like he can read his mind, then taps at Dean’s chest, fighting off a smile. “C’mon, man. Get off me.”

“Whaddya think I’ve been trying to do?” he grumbles under his breath. But he manages to flip himself off of Sam and onto his back, blinking up at the overcast moon only by virtue of his spine not being able to do much else at the moment.

“Yeah, alright dudes,” that irritating voice drifts over from the shoreline. “So just make your way down here, and then we can totally get this caravan on the road. It’ll be super awesome.”

Dean muscles himself up onto his elbows and sort of gets half-upright, most of his weight resting back on his hands—and then pauses again when his new sitting position brings him in the direct eye line of his stupid, awkward tail. He tightens his jaw determinedly and does his best to ignore it, but each slight movement seems to send it wriggling and it’s really starting to gross him out.

Sam lets out a muffled sound of exertion from beside him and somehow manages to heave himself up onto his arms, but then he pauses awkwardly, seemingly at a loss on what to do from there.

“Yeah, awesome,” the merman calls cheerfully from the water. “You guys are like halfway there. Good job.”

“Really don’t need a pep rally,” Dean bites out, then turns his attention back to the (unfortunately) inescapable tail in front of him. He’s been intentionally avoiding touching the thing the entire time. But pretending it isn’t there isn’t making it go away any faster, so Dean sucks it up and hesitantly spreads a hand out across what _should_ be his thighs.

It’s mostly awful. Smooth and cold and slick. Like a fish. Which makes perfect sense, because that’s what Dean guesses he is now. A goddamn fish. His tail catches and slides up along his brother’s as he struggles to get himself facing in the right direction, and he tries not to shudder at the strangeness of it all. Dean has never particularly liked slimy things and now he _is_ a slimy thing—they both are—and he’s starting to feel like he’ll never be in a good mood again.

Sam’s arms tremble slightly under the added weight as he holds himself still. “Hey, Dean,” he says. “I’m really thinking we should tuck our clothes away somewhere.” He pokes his tongue against the inside of his cheek. “Or it’s gonna be a little awkward when we, uh…come back up here. Afterwards.”

“Sure,” Dean says caustically. “I’ll just run up and drop them off at the nearest dry cleaners. How does that sound?”

Sam sighs dramatically, then says, “I just meant behind one of the rocks or something.”

Dean lets out a few, choice words under his breath, but has to admit that his brother’s got a point. He doesn’t have to be happy about it though. “Seriously,” he growls. “If there are crabs and jellyfish and shit all over our stuff when we get back, I’m gonna be pissed.”

“Jellyfish don’t live above water,” Sam snits.

“So not my point, Sam.”

“So, yeah…” the merman calls. “Totally not trying to rush you guys or anything—seriously, take your time—but I feel like maybe we’re racing the clock a little bit here? If you don’t want any other humans to see you?” He flinches at Dean’s renewed look of hatred, and then quiets down for a few precious minutes of peace.

Somehow, between him and Sam, they manage to collect all the sandy bundles of their assorted clothing, and their handguns (which are gonna be so covered in grit by the time they get back that it’ll probably take Dean a _week_ to clean all that shit out), and shove them in between a few of the larger crags along the jetty. Dean bitches about crabs one more time, Sam ignores him with the patience of a saint, and they finally make their halting, painful way down the rest of the beach.

The sand scrapes roughly against Dean’s heavy tail with every drag of his arms and he’s absolutely certain that they look ridiculous, but Sam’s expression of intense determination spurs him on, and he makes it down to the edge of the breaking waves just in time to see his brother flip himself out past the drop-off. There’s a brief flash of pink, the merman lets out a supportive cheer, and then Sam’s head pops back up above the surface.

“Dean, you okay?” His brother slicks his soaked hair back from his forehead with one hand, then gives him a concerned glance. “Do you need help?”

“Oh my god, this is so stupid,” Dean says, mostly to himself, but still loud enough that he knows Sam will be sure to hear him. He drags himself a little closer to the crashing waves, then sputters as an unexpected upswell knocks him a few feet back up onto the sand.

Sam immediately glides up as close as he can get, unfairly graceful for a guy whose legs just disappeared, then intentionally beaches himself. He reaches out for Dean’s hand until they can get a solid grasp on each other’s wrists, then he tugs him up against his chest and flips them both the rest of the way in.  Dean flinches automatically at the sudden splash, but squints a cautious eye open once he easily acclimates to the new surroundings. He’d expected the water to be freezing, but he’s actually surprisingly comfortable. Must be another side-effect of the mermaid thing. And other than the emotional trauma, and the fact that he probably left a few scales behind during his drag down the beach, he feels mostly okay.

Sam glances down at Dean, still plastered against the front of his chest, and grins. “That was just embarrassing, man,” he says teasingly. Then laughs like an asshole as Dean shoves himself away from his brother’s hold.

“Alright,” the merman drawls cheerfully, stretching out each syllable. “Official introduction time. Welcome to my pad.” He spreads out his arms, then taps a hand to his own chest. “I’m Zack, and I will totally be your guide through the beautiful Casco Bay.”

“Wait,” Dean interrupts. “Your name is Zack?” He raises an eyebrow. “Seriously? You’re a mermaid named _Zack?”_

“It’s short for ‘Zachary’, if that helps, man.”

A quick glance reveals that Sam looks just as lost as he feels, so he decides not to press the issue. Dean looks back to the merman in front of them, but the guy’s still pleasantly smiling, frozen in place with his hand outstretched expectantly.

Sam balks at the extended pause until he seems to realize that Zack is waiting for introductions. “Oh, sorry,” he starts. “Uh, I’m Sam. This is my br—this is Dean.”

Dean huffs out a quiet laugh and scratches at the bridge of his nose. It was a good catch. The whole ‘brothers’ thing probably isn’t the best way to go, considering how Zack had found them back up on the beach. 

Zack grins and claps his hands together, like the world’s most mellow tour guide. “Okay, nice to meet you. So I figured I’d take you down to meet my shoal, and then we can head over to the bad dude’s hideout tomorrow eve. Pretty solid plan, right?”

Dean snaps out to clutch at his brother’s bare shoulder as another wave swells past them. “Why don’t we just go now?”

“No way, dude. Check out the lady moon.” He lifts up a hand to point skyward. “You gotta respect Mother Nature. The tide won’t be right until tomorrow night.”

“I really don’t give a damn about the _tide_ ,” Dean says, purposefully ignoring his brother’s throat clearing of disapproval. “Let’s just get this thing over with.”

“Nah, man. I mean we can’t.” Zack lifts up a cupped handful of water and lets it splash back down against the surface. “Hombre doesn’t need the sea the same way us Mers do. So he can check out anytime he likes. But there’s no way we’re getting in until those cave tunnels are fully submerged.” He lets out a light giggle. “Can’t swim through air, dude.”

“Great,” Dean mutters. “So he lives in a cave. Like some half-assed Bond villain.”

Sam makes a face. “I think he’s got the right idea, Dean. Plus, we’re gonna need some more info before we run in all half-cocked.”

“Right on, man,” Zack crows, then thumps his brother on the back. “Plus, you’ll love my shoal. They’re super into humans, so you guys will fit right in.” He pauses for a second, looking slightly uncertain, then seems to change his mind and grins good-naturedly. “Okay, let’s do this. Follow me, dudes.” Zack gives them one final glance with his weird, colorless eyes, and plunges below the waves.

Sam raises his eyebrows at the sudden dive, then takes in a last breath of air. “You ready?”

“No, Sam, I am not _ready_ ,” he snaps without really meaning it. “This is friggin’ weird.”

Sam nods absent-mindedly (clearly not paying any attention to a single word Dean’s said), licks his lips, and then disappears as he suddenly ducks under the water himself.

“Oh, for fuck’s sake,” Dean says under his breath. He watches for a few minutes, but can’t make out a thing below the dark, churning surface. His brother’s drowned corpse doesn’t wash back up though, so he figures the whole breathing underwater thing probably works. Dean clenches his fists a few times, shakes his head in disbelief, and then follows Sam down into the murky depths.

The first thing Dean notices is that he can see a lot more than he thought he’d be able to. The few, faint rays of light that manage to make it past the surface tint everything a dusky gray color, but he can easily make out the outlines of Sam and Zack a few feet away. Sam seems to be testing out his range of motion, the red glint of his tail gliding back and forth in lazy figure-eights, and Zack is chilling by a shelf of dark rock, patiently waiting for him to get adjusted. 

The second thing Dean notices is that he’s still alive. He lightly runs a hand along his ribs as he tries to get used to the feeling of breathing out the side of his torso. It’s mostly unnerving. He takes a deep breath—er, or _gulp_ or whatever—then lets it out through his mouth instead, and a trail of bubbles float up to the surface. He frowns and does it again. Alright… Dean shrugs and moves past it. At least it’s still air, sort of.

“Okay, Dean. Come on, you have to admit it.” Sam swims over to hover in front of him. “This is a _little_ neat.”

Dean raises an eyebrow. “I admit nothing.”

His brother laughs, and Dean frowns as the sound bugs him. It’s Sam’s voice, and Dean can hear him as clear as day, but the timbre is all echo-y. Like that old tape of whale songs Sam had made them buy when he was fourteen. It was supposed to help people sleep or something, and his little brother had dug his heels in and thrown a fit about needing it until Dad had finally caved. And even an eighteen-year-old Dean had to admit that it was actually surprisingly soothing. They’d ended up throwing it on whenever Sam would curl up in the back on one of their long drives, and it wasn’t until Dad had almost wrapped them around a tree, eyelids drooping in the driver’s seat, that they’d had to toss it. And Sam had stoically accepted the inevitable return to Alice in Chains with all the teenage forbearance of someone who _didn’t_ want to die in a fiery car wreck.

“I bet you’re totally one of those pool guys, huh, Sammy? Deep down? The ones who do laps and shit.” Even though Dean is expecting it, the resonance of his own voice still startles him a little. Like his reverb dial has been set too high.

Sam scoffs and a ring of bubbles briefly halo his head. “Do you have any idea what’s in most motel pools?”

“Yeah, I do,” Dean says. “Which is why I’m never in them.” Sam’s hair floats up around his face, all delicate and girly as he rolls his eyes, and Dean has to fight back a fond smile. “Yeah, okay, Little Mermaid,” he gripes teasingly. “How about you stop fucking around so we can get this stupid thing over with?”

“Please,” Sam grins. “Look who’s talking, asshat.”

Dean attempts to cuff the back of his brother’s head, but it’s way harder to move while completely submerged in water and Sam easily dodges the hit. He tries to swim after him, intent on making his brother suffer one way or another, but just ends up lurching sideways when he can’t quite get his tail to work right.

Sam is immediately back at his side, latching a hand around his bicep and pulling him level. “You got it?” he asks, carefully keeping his hand out until Dean manages to get steady.

Dean growls as he flails his arms uselessly. “Do you think this is the strangest thing that’s ever happened to us? ‘Cause I’m kinda thinking that this is the strangest thing that’s ever happened to us.”

Sam gives him the most exhausted look he’s ever seen. “I was a _car_ once,” he says dully, and Dean chokes on water as he tries not to laugh.

“I forgot about that,” he admits, way more amused than he should be. And all of a sudden, their current situation doesn’t seem quite so bad anymore.

Sam keeps a steadying hand against the back of his shoulder blade as Dean gets his head around swimming in a straight line, and they eventually both make it over to where Zack is waiting for them, Sam still carefully flanking his side like an aquatic set of training wheels. Dean’s brain suddenly flashes back twenty-two years or so, to when he was teaching a much smaller Sam how to ride that old, rusted-out bicycle they’d found tucked around a corner of Bobby’s scrapyard.

“Okay, guys,” Zack says. “You’re all good, right? Awesome. So just follow me and keep close and we’ll get there in no time.” He starts to head off, then turns back to face them. “Oh, also,” he adds as an afterthought. “It’s not like there are a ton of gnarly things down here, but you still might wanna watch out for boats and stuff, y’know? You guys are kinda… _bright_.” Then he gives them one last grin and jets off, leaving him and Sam scrambling to catch up. 

They trail after their annoying new acquaintance, ducking around and under the seemingly endless cays—and despite the lengthy swim, the waters remain shallow enough that Dean can still clearly make out the dark silt of the ocean floor beneath them. He glances over to Sam’s tail and then his own, and he does have to admit that they do kinda look like some sort of weird, fishy Christmas. “Why is that, by the way?” Dean asks belatedly, following the flip of Zack’s more muted gray scales. “The color thing, I mean.”

“Dude,” Zack calls back over his shoulder, voice as calm as a zen guru. “Mers look the way they look, y’know? That’s just the beauty of life, man.”

Dean glances to his left to catch his brother’s subdued smile, then deliberately rolls his eyes at their guide’s psycho-babble.

Sam snorts, and a flurry of tiny bubbles float up past his face. “I think it’s kind of sweet actually,” he says quietly.

“If he calls me ‘broski’, I’m gonna start throwing punches.”

“Can you even punch underwater?” Sam pulls a hand back and forth as he tries it out. “I don’t think it would hurt very much.”

“Whatever. Dude’s a toothpick. I could breathe on him and he’d break.”

“Not sure you can breathe underwater either,” Sam adds with a teasing smile.

Dean shoots a stream of bubbles directly at his brother’s smug face, and Sam laughs as he concedes the point.

They follow Zack down through the twisting ledges of rock, barely managing to keep him in sight for the entire trip. Dean gets a decently solid handle on swimming with a tail after about ten minutes or so, and starts to edge up on his brother. Sam makes it very clear, without even saying a word, that he knows exactly what Dean is doing and that he refuses to play along. But he still hits him with a bitchface every time Dean pulls into the lead. They finally make it to wherever Zack’s been taking them (Dean couldn’t navigate the way back if you paid him) and Sam crashes into Dean’s back as they both try to brake at the same time.

“Shit, sorry. I’m sorry,” Sam mutters over and over, wrapping his hands around Dean’s shoulders and trying to pull them both back up.

Dean shoos his brother away with an annoyed flick of his wrist. “Yeah, yeah, I got it.” He untangles his arms from Sam’s and gets himself somewhat upright. “You friggin’ gorilla.”

Zack smiles brightly once they focus their gazes back on him, and he sweeps his arms out at a dreary-looking row of caves behind him. “ _Me casa es su casa_ , dudes. Welcome to my humble abode.” Sam plasters a painfully-polite smile across his face, but Dean just lifts an unimpressed eyebrow at the sight. “So, I’m gonna go let my shoal know we’ve got some company,” Zack continues blissfully, grinning from ear to ear. “I’ll be right back. Seriously, two shakes.” He slips away, tail flipping nimbly through the water, and pokes his head into a couple of the caves down the line.

Dean watches him for a few seconds before turning his attention back to his brother. “I think it’s important to remember that no matter what happens, this entire thing is your fault,” he says out of the corner of his mouth.

Sam just rolls his eyes.

“Okay, guys,” Zack calls out from the briny distance, tugging another figure behind him by their clasped hands. He settles in front of them, then pulls the other mermaid around until they’re side by side. “This is my girl, Lydia.”

She’s even smaller than Zack, delicate and thin-boned, and with the same creepy, colorless stare. Lydia isn’t wearing a single stitch of clothing other than a cheap, plastic necklace looped around her slender neck and Dean’s gaze immediately lasers down to her uncovered tits. And he must end up staring for a while, because Sam sharply flicks at one of the gills on his ribs until the snap of pain brings his head right back to center. Dean guiltily clears his throat and tries to focus back on something innocuous, like her necklace. It kind of reminds him of one of those crappy toys you can score for a few tickets at an arcade, the bright yellow coating already chipping off most of the beads. He raises his eyes back up to meet hers, but she just stares at him like she’d never stopped, gaze dull and uninterested. The heavy line of her dark bangs makes her seem even less approachable than the unblinking glare does.

Dean tosses her his most charming smile, trying to break the ice. “That’s a nice necklace you got there, darlin’.”

“It’s ironic,” she says bluntly.

“Okay.”

Sam bites back a quiet laugh at his expense, and they all hang there in Lydia’s awkward silence until two more figures drift up out of the murky water.

Zack beams at their arrival, completely relaxed, like they hadn’t been clumsily staring at each other just a minute ago. “And this is Wanda and Andre. They’re mated too,” he adds with an enthusiastic whisper.

Dean’s going to assume that the chick is ‘Wanda’. She’s thin as well, ribs jutting against the skin of her sides, and Dean’s starting to think that Zack wasn’t lying about the whole ‘asshole monster is stealing our food’ thing. Wanda’s just as naked as Lydia, but completely unadorned apart from the tightly curled hair heaped onto her head, so pale blonde that it’s almost white. She also seems to be trembling slightly with each passing current.

Andre swims up behind her and places a casual hand along Wanda’s waist until she stills. He’s darker skinned than the others and completely bald, but the scowl on his face is what really sets him apart. He’s taller than the rest of Zack’s ragtag little shoal, but still doesn’t even come up past Dean’s shoulder. Sam practically towers over the lot of them.

“This is Sam and Dean,” Zack says cheerfully. “Sam and Dean, meet my shoal. Guys, meet Sam and Dean.”

Wanda lets out a nervous little trill, but Andre doesn’t break his glare. “You’re humans,” he says darkly. He flicks his gaze up and down Sam’s body and his lips twist sourly. “Our own magic can’t fool me. Why are you here?”

“I brought them, man,” Zack says, placating. “They’re gonna help us stop that dude who’s harshing our buzz. They’re _hunters_.”

Andre snorts and narrows his pale eyes, but doesn’t say anything more.

Sam hesitates at the heated stare being fired his way and switches his focus to Wanda instead, gaze so intentionally above-the-neck that it’s painful. “He’s been hurting humans too,” he says gently. “We’re just here to help.”

Andre bristles again, probably pissed that Sam’s talking to his girlfriend or whatever. “Help?” he scoffs. “Humans? The only thing your kind has ever done for us is to force us into the shadows. Hiding like eels among the bones of the corals which you _also_ destroy.”

“Not all of us,” Dean drawls casually, interjecting before Andre can do something _really_ stupid, like get worked up enough to make a move on his little brother. “Sam here gets a monthly ‘save the reefs’ newsletter. Ain’t that right, Sammy?”

“Dean, you’re not helping.”

“Oh,” Andre coos sarcastically. “It’s nice to know that at least the humans feel _slightly_ guilty about destroying our ecosystem and overfishing us until we starve.”

“C’mon, man,” Zack says weakly. “That’s the nix, not the humans.”

Dean narrows his eyes. “Wait, what?”

“Sure, because food was _so_ plentiful before,” Andre shoots back at Zack, completely ignoring the interruption.

“Look,” Sam says, deliberately calm. “Andre, you’re right.” He holds his hands up defensively, meeting the merman’s glare with cool restraint. “It isn’t right what people have done. And if I could fix it, I would.”

Andre sneers again. “I wasn’t asking _you_ ,” he spits. “ _Human_.”

Dean jerks forward and snarls, “Sam’s just trying to help, jackass,” at the exact same time that Sam throws a restrictive hand over his chest, overlapping with an emphatic, “Dean, don’t.” And Andre pulls back his shoulders, straining against Wanda’s tremulous hold on his arm, and looking for all the world like he’s just waiting for an excuse to launch himself at Sam’s throat.

“I like your tattoos,” Lydia says out of nowhere. Casual, like it isn’t barely the second thing she’s said this entire time. It cuts through the tension like a knife, and after an uneasy minute, she returns to her silence, drifting off with a bored expression.

“Uh…thanks,” Dean says haltingly, not letting Andre out of his sights until the guy finally appears to calm down. But when he glances over, Lydia isn’t looking at them at all anymore, apparently completely disinterested in the conversation once again.

Zack clears his throat and a swirl of small bubbles drift free. “Okay, so…” His eyes flick back and forth until he seems somewhat confident that no one’s planning on throwing a punch. Or whatever the mermaid equivalent is. Dean would probably go for a grapple, first thing, if the situation called for it. He’d bet on himself being strong enough to at least break an arm or two before they could deal any serious damage in return. Andre’s the biggest, and he still can’t be more than ninety pounds or so, wet. Ha.  _Literally_. Zack’s voice warbles a little, tight with nerves, as he tries to salvage the earlier peace. “So…if you guys are gonna help us, you’ll need some 411. Yeah?” He relaxes a little at Sam’s sympathetic nod. “Okay. So, yeah. Nix. That’s what the dude is. He got here right after we did.”

“You’re not from here?” Sam asks.

“Nah,” Zack breathes, clearly relieved to be on a less divisive topic, despite the interruption. “We swam up from Baja, man. That’s more my scene, but Lydia doesn’t like the heat. I thought I could take her up here to see some of the lighthouses. Real touristy junk, y’know? ‘Cause I’m a classy guy.”

Dean huffs out a sarcastic laugh under his breath. “Sure, that was my first impression of you.”

Sam gives him the evil eye, but Zack doesn’t look anything other than lightly flattered as Dean’s insult flies right over his head. “I think what my brother is _trying_ to say,” Sam grits out, “is that he’s a good judge of character.”

Dean’s eyes widen at the careless mistake. “ _Sam_ ,” he says urgently, under his breath. 

But the warning is apparently unnecessary because Sam seems to come to the exact same realization just a second later, suddenly sputtering as he tries to backpedal. “Shit, no. That’s not what I meant.” He laughs nervously, fooling no one. “Did I say brother? I meant...” Sam swallows, stalling for time. “Obviously, I meant—”

“Whoa, hey,” Zack croons reassuringly, apparently still perfectly content with any conversation as long as it means no one is fighting. “No judgment here, friend. We are all children of the Mother.” He’s talking about Eve, the way he says it. Dean’s sure. Like he can clearly hear the capital M behind the careful pronunciation.

Wanda quails a little at the name, and Sam looks like he really doesn’t want to touch this one with a ten-foot pole, but Dean can’t help but step up to the plate. “Yeah, well,” he chuffs, chest out a bit. “Don’t worry. I doubt _Mother’s_ gonna be coming around for a visit anytime soon.”

“What does that mean?” Wanda whimpers nervously. She spins around to clutch at Andre’s bicep. “I don’t know what that means.”

“It means that we ganked her ass,” Dean says, ignoring Sam’s noise of exasperation from behind him. “Dead as a fucking doornail. You’re welcome.”

“You two _killed_ the Mother?” Andre’s eyes flash and he strains against his mate’s hold on his arm. Looks like it might be a regular thing for these two. “You murdered the inceptor of our species?”

Sam lurches up beside Dean with an awkward flick of his tail, then straightens as best he can, trying to present an imposing, united front. “She was killing humans,” he says firmly. “Slaughtering them. We were just protecting others from getting hurt.”

There’s an uneasy moment of silence, and then Zack coughs awkwardly to smooth over the second bout of tension. “Ah, well that’s all good then. Right, Andre?” Andre continues to glare coldly, but doesn’t say another word.

“She wanted us to make more Mers,” Wanda says, voice trembling. “She came to us in our heads. It’s why we created the charms.” She gestures at the string around Dean’s neck—or maybe it’s just another muscle spasm—before she continues. “But we encounter humans so rarely, and it’s such a distressing possibility to think about. Meeting humans, that is…” Her voice tapers off as she stares out into the distance for a long moment, apparently forgetting that she had even spoken in the first place.

“We tossed around the idea of laying eggs,” Zack says brightly, picking up the slack like Wanda had never paused. “But I’m just not sure I’m ready for kids, y’know? It’s such a mega commitment.”

“The children are our future,” Lydia declares coolly, and Zack wraps an arm around her bony shoulders.

“That is so true, babe.” Zack beams down at his girl, then lifts his eyes up to catch theirs. “You totally gotta snap up the smart ones, am I right?” He levels a conspiratorial look at Dean, then winks. “This guy knows what I’m talking about.”

Dean rolls his eyes and elbows his brother in the ribs before he can say something smug, then winces at Sam’s gasp of pain. Gills. Right. He’d forgot. He chances a look, but Sam is just glaring at him like he’s planning the next six years of revenge. Dean must come off slightly guilty though, because his brother’s expression softens after a few seconds. Maybe it’ll only be three.

“This is not the time for children,” Andre says darkly, breaking the moment. “How could anyone want to bring young into a world where there are humans about?”

Zack clears his throat again. “Uh, hey, Wanda. How about you go take Andre for a swim, huh? ‘Till he calms down?” Wanda twitches her chin, or maybe it’s a nod, and tugs at Andre’s arm until he finally lets himself be dragged away, glaring daggers the whole time. Zack immediately perks up as soon as they’re gone. “So, pro hunter dudes,” he says brightly. “How are you gonna stop mondo jerk dude and save all of us?”

Sam turns his attention away from where he’d been watching Andre go, and coughs a little self-consciously. “Uh, well you said he was a nix, right?” Zack nods cheerfully. “So bronze, I guess.” He lifts a shoulder. “You think you know where we could find some by tomorrow evening?”

Zack lets out another rambling laugh, and even Lydia scoffs against his side. “What do you think, babe?” he coos. “You think we could find some bronze?”

Lydia quirks up one side of her mouth into a wry smirk. “I dunno,” she monotones dryly. “I guess I’ll have to check.”

“Ha! Yeah, right.  _Check_.” Zack brings his head back up to grin at them. “Lydia’s got the most banging collection of junk you’ve ever seen, dudes. Isn’t that right, babe?” Lydia doesn’t speak, remaining faintly and silently smug under his arm. “She can totally get you whatever you need.”

“Uh, okay. Great,” Sam says. “We’ll just wait here then.” He flicks his eyes to Dean. “Right?”

Dean hums in agreement and pastes a tight smile onto his face.

“Radical,” Zack crows happily. “We’ll be right back. I’m sure Lyds has something back at our cave that will totally fit what you guys are looking for.”

They swim away, hand in hand, and Dean waits until they’re completely out of eyesight before snapping his hand out. He grabs at Sam’s uncovered nipple and twists until his brother yelps. “What the hell is the matter with you?” he scolds under his breath. “Going around and telling them we’re brothers like that. Rookie fucking mistake, dude.”

“ _Ow_ , Jesus!” Sam curls in on himself, tail flailing wildly, but Dean doesn’t let go. “Fucking stop,” he finally snaps, shoving Dean off and rubbing at the abused area. Sam throws him a sullen glare. “ _Sorry_. I’m not used to people, y’know, _catching_ us like that. It slipped out.” He rubs at his chest again. “Plus, that Andre guy was freaking me out.”

“Well, just—don’t do it again,” Dean mutters ineffectually. He runs a hand over his face and grudgingly lets the slip-up go. “So, what was that you guys were talking about? The Knicks?”

“Nix,” Sam corrects him. “N-i-x. They’re kind of like the male counterparts to sirens.”

Dean chuckles. “Figured it would be weird if Carmelo was actually behind all this.” Sam very intentionally does not laugh at his joke, still intent on acting like a pissy little bitch, so he moves on. “So what, they prey on chicks? Get ‘em to kill their husbands?”

“Sort of,” Sam sighs, wiggling a hand. “They lure women in—like sirens do with men—but it’s more of a ‘to their death’ kind of thing.”

“But women weren’t the only ones reported missing. There were at least two or three guys on the list as well.”

Sam frowns as he thinks over the point. “Zack seemed pretty sure of what this guy is.” He scratches at the back of his head. “Maybe he’s not picky?”

Dean makes a face. “You mean like Bowie?”

“ _Dude_.”

“I’m kidding. Go buy a sense of humor.” Dean lets out a waterlogged sigh and changes the subject. “Okay…so do we kill it the same way? Blood of an affected sailor and all that?” He tilts his head. “Is there a name for lady sailors?”

“Women weren’t allowed on boats,” Sam says informatively. “But, no. I don’t think so. Lore says you can stop a nix if you know his name.” The corners of his mouth tug down. “Not really sure how or why that would work though. We should probably just stick to bronze.” He chuckles. “Guess we should have grabbed our net, huh?”

“Too late now,” Dean shrugs. Then he tilts his head. “How do you _know_ all this shit, by the way?” he asks teasingly. “Do you really love research that much, or is it a sex thing?” Dean swims up close and fixes his brother with his best serious face. “It’s okay, Sammy, you can tell me.”

“Dude, shut up,” Sam laughs, his earlier attack apparently forgiven. “I looked it up back during the siren case. Because that’s sort of our _job_ , remember?”

“Sure. Whatever you’ve got to tell yourself in order to sleep at night.”

“Fuck you.” Sam shakes his head in reluctantly amused defeat, and Dean curls an affectionate hand around the back of his brother’s neck.

“Alright,” Dean sighs. “So we’re dealing with some kind of mysterious dude-siren and we’re just _hoping_ that bronze is gonna work on him.” He lets in a mouthful of salty water, then spouts it back out again. “Well, on the bright side, at least Crowley’s off the table for now. With all this salt we sure as hell don’t gotta worry about demons.”

Sam trails his hands through the water between them, tilting his neck back into Dean’s absent-minded massage. “I’m not sure if saltwater’s pure enough, actually.” He thinks for a moment. “Maybe.”

“Man,” Dean whines. “Don’t kill my bright side.”

Sam bites at his lip for a bit before he speaks, a stupid nervous gesture he’s never quite grown out of. It makes him look like he’s all of twelve again. “Do you think he’s still alive?” he asks quietly.

“You do,” Dean says, trying not to inject too much bitterness into his tone. “Bobby too, apparently.”

“ _Dean_.”

“And—oh, that’s right,” he continues, dropping his hand from Sam’s skin. “You both think that Cas is the one behind it all. In some super secret Legion of Doom pact.”

“Dean,” Sam says with his best put-upon sigh. “We’re just saying _maybe_. You can’t honestly tell me it isn’t a possibility.”

“Of course I can. Sammy, this is _Cas_ we’re talking about.” He grabs at his brother’s chin, tipping it to meet his gaze. “And he said he isn’t, so he’s not. Why would he ever lie to me about something like that?”

Sam’s gaze wavers the slightest bit. Twitchy. “Because he wants you to like him,” he says grumpily.

“Oh, _come on_.” Dean makes a face. “You sound like fucking Balthazar, dude.”

“Well, maybe he has a point.”

“No. He doesn’t have a point,” Dean snits, letting go of Sam’s face. “He just has a smarmy British accent, so it sounds like he actually knows what he’s talking about.”

Sam sighs and glances down at his hands. “I’m just saying.”

“Well, _don’t_.” He pins his brother with one last end-of-discussion look before Zack and Lydia come swimming back up to meet them, leisurely as can be.

“Yeah, so I guess I can part with this _one_ ,” Lydia says in greeting, making it blatantly clear that she’s being particularly generous with her sacrifice. She presses a small knife into Dean’s outstretched fingers. “But, it’s like one of my favorites, y’know? So you’re _welcome_.”

The blade is fairly small, maybe a little past the full length of Dean’s hand if he was in his normal body. As it is, it comes just short of his creepy, unnaturally long fingers. It’s definitely bronze, with a solid black handle, and the word ‘THAILAND’ carved into the base along with a depiction of some minor god. “So, what?” Dean asks, toying with the knife in his palm. “This some kind of ancient Thai dagger for rituals and shit? How’d you get hold of it?” He strokes his thumb down along the blade, then hisses as it burns his skin, along with a worrisome sizzling sound.

“Careful,” Sam scolds, “you’re just as Mer now as they are.” He frowns and runs a finger over the handle. “Y’know, it actually looks pretty modern.”

“Uh, yeah,” Lydia says, like she’s talking to an idiot. “That’s ‘cause it’s from the Thai restaurant a few blocks up past the beach. They dropped a load of cheap silverware overboard the last time their fishing boat sailed through.” She scoffs and shares a mocking look with Zack. “Why would I have an ancient bronze dagger in my junk collection? If something’s actually expensive, then it’s not kitsch anymore.” She rolls her eyes. “Obviously.”

Zack smiles back at her, completely besotted. “Yeah, man,” he says distractedly. “Don’t be ridic.”

“Right. Of course,” Dean says sarcastically. “My mistake.”

Sam gives him an admonishing flick with his tail, and the gross texture makes him squirm a bit. “Thank you,” his brother says, with a not-so-subtle emphasis that’s clearly meant for Dean’s benefit. “This is really helpful.”

Lydia just stares off into the water again. “Yeah, whatever. I’m pretty much over it now, anyway.”

“How convenient,” Dean says flatly, and easily avoids his brother’s second flick of rebuke.

“So, I think we’re probably gonna head back to our place,” Zack says. “Getting late, y’know? You guys are totally welcome to one of the empty caves for the night, if you want. Way smarter than staying out in the open like this.” He glances over his shoulder, a little anxiously. “Just—the one near the back is Andre and Wanda’s. So maybe steer clear?” Zack shrugs. “He’s always been a little hot-headed about humans, but he’s totes a good guy when it comes down to it.”

“Good to know,” Dean mutters.

“Yes, we’d love to stay here tonight,” Sam says way too loudly, drowning out Dean’s sarcasm. “Thank you.”

“Yeah, no problemo,” Zack says, perfectly mellow. “I’ll see you dudes tomorrow then. And I’ll take you over to those cave tunnels I was telling you about.” He tosses them a casual, two-fingered salute and then tugs Lydia behind him as they head back toward the row of caverns.

“Guess the net wouldn’t have worked anyway,” Sam says once they’re gone, eying the knife still clasped in Dean’s fist.

Dean grunts noncommittally in response, then changes the subject. “So we get to stay in a cave tonight, huh?” he says bitterly. “Lucky us.” Dean glances down at himself, and then remembers just how much he hates his life. He tries to pull his legs apart, out of futile self-pity more than anything else, but his tail just twitches.

Sam looks like he’s fighting off a smile. “Better than some of the shitholes we squat in. You gotta admit.”

“That’s not really saying much.”

His brother laughs. “Yeah, fair enough.” Then he swims forward and tugs at Dean’s shoulder. “C’mon. Might as well get settled before Andre and Wanda come back.”

“You afraid of the scary mermaid?”

Sam rolls his eyes. “More worried about what _you’ll_ do if he looks at me funny again.”

Dean scoffs. “We need to work on that ego of yours.”

“Yeah, sure.  _I’m_ being unrealistic.” Sam leaves Dean in his dust—er, _silt_ —and swims up to the row of cave mouths, trusting him to follow. He ends up picking a spot somewhere in the middle, noticeably distant from the one on the end that Zack had warned them about, and flits inside.

Dean catches up just as Sam pops his head out again. “What?” he asks cautiously.

“Nothing.” Sam glances back a little distractedly. “That one’s kind of small. I’m just gonna check…” He turns and jets over to the neighboring rock, ducking his head in and out, before returning to Dean’s side. “Uh, guess they’re all kinda—” He cuts himself off and glances at Dean. “Looks like it’s gonna be a little cramped tonight,” Sam says. “Unless you wanna grab separate ones.”

“Yeah, right,” Dean grumbles. “Like I’m letting you out of my sight while we’re thirty below.” He shoves Sam back into the first cave with his free hand. “I’d probably wake up and find out that your necklace has malfunctioned or something. And tell me, Sammy, how the fuck am I supposed to give CPR to a mermaid?”

Sam gives in and willingly heads inside. “Fine,” he sighs. “But you’re not allowed to bitch at me when it’s too small.”

It’s too small.

The cave is maybe eight feet wide, either way, and shallow. Dean can’t even extend his arm to its full length without knocking his knuckles against the rocky ceiling. And it’s dim, even with their weirdo eye things. He opens his mouth to make some sort of complaint, but his brother just gives him a look.

“What?” Sam says irritably. “I told you, man”

And Dean doesn’t have anything to say in his defense. So he just grumbles under his breath and stabs Lydia’s knife into the sand near the cave entrance, burying it to the hilt until he’s sure it’s not going anywhere. “So,” he says tiredly, spinning around to face his brother. “Guess we’re stuck here until morning.” Dean pats down his sides. “Wish I had a deck of cards or something.”

Sam snorts. “Yeah, in what pocket?”

He can’t help but give Sam a shallow smile in reply. “Yeah,” he admits. “And if I _did_ have pockets, booze would definitely be top of the list.”

“Shocker.”

Dean trails his fingers along the side of the rough wall, intentionally ignoring his brother’s snark. “So, any other bright ideas to pass the time? Feel like chatting?”

“Look, Dean,” Sam says, anxiously twiddling his fingers. “About Cas—”

“Aw, dude,” Dean groans. “C’mon. I was _joking_.”

“Well, I’m serious. About the whole Cas... _thing_.” Sam sighs and tugs a hand through his hair. “I mean, I literally saw the guy parse out the complete life story behind a half-empty can of Ginger Ale once. So I just don’t understand how he could’ve mixed up Crowley’s bones like that.” He gazes at Dean imploringly, eyes set to stun. “How does a _demon_ outsmart an _angel_ , Dean? Unless…” Sam trails off, letting the silence finish his sentence for him.

“No,” Dean says bluntly. “There’s no way in hell. _Literally._  And I don’t wanna fucking talk about it anymore.” Mostly because the more points his brother brings up, the more everything starts to make a morbid kind of sense. He shoves the sinister thoughts out of his head and steadfastly refuses to even entertain the notion. Cas has done nothing but trust them, over and over again. The least Dean can do is return the favor.

Sam throws his hands up. “Look, Dean, I’m just saying. He’s been all tangled up with his war, right? So maybe somehow he got all tangled up with Crowley too.” He raises a catty eyebrow. “And now he’s lying about it because he likes you,” he adds, voice clipped.

“Because he _likes_ me?” Dean repeats so dryly that it wouldn’t be surprising if the water evaporated around them both. “What are we, in 5 th grade? That’s ridiculous. I need you to be aware of how ridiculous you sound.”

“It’s just… He does kind of go out of his way to help you whenever you need him. And he answers all of your prayers, every time you call. Not so much with me, y’know?” Sam twists his lips. “Maybe a cigar isn’t always just a cigar.”

Dean rolls his eyes. “I literally have no idea what you’re talking about.”

Sam crosses his arms over his chest and his tail fins twitch agitatedly over the sandy floor. “It’s not like I don’t get what he sees in you,” he continues on, snippy. “’Cause I’d be lying if I said I didn’t feel the exact same way.”

“Aw, Sammy,” Dean simpers. “You like me? Or you _like_ -like me?”

“Dean, c’mon,” Sam says tiredly. “I’m being serious.”

“No, you’re being stupid. This whole conversation is stupid.” Dean raises his fingers into a quick, zipping motion. “And we’re done talking about it.  _Capisce?”_

“…Fine,” Sam eventually grits out. Because he’s a big, jealous bitch who gets himself worked up over nothing all the damn time. Sam shrugs his shoulders and shuts up about it, but he looks so downtrodden over the whole thing that Dean can’t help but try to smooth it over.

“Look, Sammy,” he says, drifting closer. “There’s nothing we can do about it right now anyway. So let’s just drop it and deal with it when we have to.” He nudges his brother’s arm. “Okay?”

Sam opens his mouth like he wants to press the issue, but then gives up instead, letting his shoulders drop. “Yeah, okay,” he sighs. “I’m sorry. You’re probably right.”

“I always am.”

“Okay, now you’re pushing it.” Sam glances up with a wry smile, then blinks once their eyes catch, flinching almost unnoticeably.

Dean frowns. “What?”

Sam shakes his head and stares back at him, intentionally holding the gaze this time. It kinda reminds Dean of the awkward way you very definitely _don’t_ stare at someone’s hugely obvious deformity the first time you meet them, trying to keep strained, polite eye contact through the whole conversation. “Nothing,” Sam says. “It’s just—you look different, y’know? It’s kinda freaking me out a little bit.”

Dean looks down at his too-soft hands and thumbs at the pale webbing in between his fingers. “Yeah,” he grumbles. “Well, you ain’t the only one.”

“It’s your eyes, man. They’re kinda creepy.”

“Right back at you, tiger,” Dean gripes, a little self-consciously.

Sam huffs out a quiet laugh, barely there at all. It’s more of a hitch of his chest than anything else. “Point taken,” he says. Then he slowly places his hands on either side of Dean’s face and studies him with that unnerving, filmy gaze. It’s more obvious now, down here in the dark, colors shimmering across Sam’s eyes every time he moves, and Dean’s sure it goes both ways. “It must be a light refraction thing,” Sam murmurs as he paws at his temples. “So that we can see this deep in the water, just like them.” He trails a slender finger across Dean’s cheekbone, then frowns. “Your irises aren’t clear though, not like theirs are. Still weird.” He narrows his own creepy stare and leans in more, continuing to prod until Dean's thoroughly annoyed. The murky light happens to catch Sam in a certain way as he tilts his head and his eyes flash gold, and Dean suddenly has to clamp down on the old spike of fear that shoots up his spine.

“Dude, get off my face.” He swats his brother away—harder than he thought it would be with the added water resistance—and snaps his tail out until he’s free from Sam’s grip. When the currents still, Dean ends up floating just the slightest bit above Sam’s eye line and the phony height difference sends a warm flush throughout his entire upper body.

It feels weird without the accompanying thrum of arousal.

Sam’s eyes go half-lidded, like he knows what Dean’s thinking, and that vibrant shine gleams out from the thinned slits, making him look even more unearthly than normal. He reaches out a slow, sure hand and gently brushes the backs of his knuckles up along the length of Dean’s tail, eyes glued to whatever his fingers are doing. “What does it feel like?” he asks quietly. Curious.

“It feels like— I dunno, like you’re touching me.” Dean swallows hard. “Which you are. So quit it.”

“Your tail is really pretty, you know?”

“Thank you, Samantha.”

Sam drifts upwards until they’re at the proper heights again, mouth tipped up into a knowing smirk. “It suits you,” he says. “All flashy and shit.” He brings his hands up to cage Dean in on either side, steadily fanning his tail to push them both up against the nearest rock wall, and then slowly tilts his head down until his lips are just a whisper-stroke from Dean’s. “Hey,” he says casually. Fondly.  “Kiss me.”

And Dean can’t help the lazy smile. “Well,” he purrs. “Since you asked so nicely and all.” He tips his chin up, catches Sam’s mouth with his own, and then groans contentedly as he relaxes into the soft kiss. Sam nips at his lower lip, sighing lightly, and Dean trails a hand down to palm at his brother’s crotch, body automatically falling into the familiar movements by rote. But his fingers don’t meet anything other than the spread of glossy scales and firm muscle, and Dean jerks back at the unexpected sensation. They both pause, blinking at each other a little awkwardly, and then Dean huffs out a low laugh, bubbles trailing up the edge of Sam’s jaw. “Sorry,” he says. “Forgot. It’s weird right?”

“I don’t know,” Sam shrugs, trying to break the discomfort by nuzzling his nose back behind Dean’s ear. “I guess I don’t mind it too much.”

“Yeah, that’s ‘cause you’re a friggin’ monk.” Sam brings his arms up to wrap around Dean’s sides, tugging him away from the cave wall and into his tight embrace, and Dean starts feeling just the slightest bit light-headed. At first, he thinks that maybe something is actually working downstairs, but then it slowly becomes harder and harder to breathe, and he has to forcefully yank his brother’s hands off of his ribs once he realizes what’s actually happening. “Hey, man,” he gasps against Sam’s mouth. “I’m all for trying new things, but autoerotic asphyxiation ain’t really at the top of my list.”

Sam’s eyes go wide the second he gets it, and Dean really tries not to think ‘gutted fish’. “Shit, Dean. I’m so sorry.” His hands flutter clumsily against Dean’s grip on his wrists. “I didn’t even think. God, I’m so sorry. That was dumb.”

He chuckles at his brother’s kicked puppy look. “It’s fine, dude. Just wasn’t really planning on ending up like Carradine anytime soon.”

He expects at least a compulsory laugh out of his brother, but Sam just fucking _wilts_ in front of him, shoulders drooping pathetically and tail fins flagging against the floor. “This is all sorts of awkward,” he says miserably.

It breaks Dean’s heart to see him so down. “C’mon, Sammy,” he says. “It’s not that bad.” Sam refuses to meet his eyes, so Dean lets go of his wrists to playfully nudge him under the chin. “Hey,” he drawls provocatively. “You wanna _spawn?”_   He waggles his eyebrows as over-the-top as possible.

His brother snorts. “You have absolutely no idea what that means, do you?”

“It’s like sex, right? Super weird, kinky fish sex.”

“Not even a little,” he says dryly, but there’s a comfortable smile curling up at the edges of his mouth, and as far as Dean’s concerned, that means he’s done his job. He flicks his fins out to twine around Sam’s—valiantly ignoring the quiver of disgust that coils in the base of his gut—and his brother glances up to meet his eyes. “So, what?” Sam asks. “Necking’s fine as long as the hands are up and out?”

Dean chuckles and tangles his hands in Sam’s weightless hair. The wet texture catches and drags around his fingers. “I think that’s a little overdramatic even for you, kiddo.” 

“Yeah sure,” Sam scoffs. “ _I’m_ the dramatic one.”

“Do you want my weird, kinky fish sex or not?”

Sam laughs outright then, sliding closer until they’re flush again. “Always,” he says warmly. The echo of his voice tingles against the skin of Dean’s neck, and he brushes a thumb over Sam’s throat in return. But his brother lets out a jaw-creaking yawn the instant he moves back in for another kiss, and Dean sighs in reluctance.

“Alright,” he says a little bitterly. “Bedtime for Bonzo, I guess. Might as well catch a few hours, since we’ve _apparently_ got nothing better to do.”

Sam hums and drapes himself even further over Dean’s shoulders. “I’ll blow you the instant it’s physically possible again,” he says drowsily.

“I’m holding you to that,” Dean mutters. Then he wraps an arm around his brother’s narrow waist and lets them both sink down, until he’s leaning back against the corner of the cave wall with Sam lounging against his chest. Kid can _sprawl_ , it’s like a natural talent or something, and his gawky, praying mantis limbs sure don’t hurt either. Dean resigns himself to cuddling for the next few hours—best way to make sure Sam won’t float away during the night, knowing their luck—and aimlessly runs a hand down and over his brother’s front. Dean pauses at the unfamiliarly hairless skin underneath his fingertips. “This is a little weird, huh?” he says offhand, circling his fingers once more. Then he chuckles and thumbs at a nipple. “Reminds me of when you used to shave. You remember that?”

Sam’s cheeks flare up so quickly that Dean’s impressed by his circulation. “Dean, shut up,” he mutters.

“What? You did.”

“Dean, I swear to god.”

“It was for all the ladies, I assume,” he drawls.

Sam makes a bitter noise and tucks his face into Dean’s neck. “God, you’re such a friggin’ jerk,” he sighs, but there’s no heat to his words.

Dean doesn’t say it back, but it makes him smile anyway.

 

~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~

 

They spend most of the next day waiting for the fucking tide to be right. Because god forbid anything could be easy. Dean spends the morning hashing out the best strategy for sneaking up on a nix, and Sam very intentionally does not bring up Cas or any Cas-related issue at all. Then Dean’s stomach starts grumbling sometime around noon, and he loudly bemoans the lack of any fast food joints under the sea, and Sam just gets all huffy and affronted at his complaining. Which he guesses makes sense, considering that the rest of Zack’s little mermaid troupe must be feeling pretty peckish themselves. So Dean resolves to hit the next Burger King they see the minute they get out of this, and spends the rest of the afternoon messing with Sam in order to get his mind off his poor, underfed stomach. It’s funny for the first couple hours or so, until his brother starts pushing back, and then they’re irritably shoving and poking and flicking at each other just for stuff to do. At one point, Sam suggests Twenty Questions out of sheer boredom (and probably bruised ribs), but exhaustedly gives up once he realizes that Dean is intent on choosing ‘the ocean’ for every single one of his turns. Apparently, “What? It’s not _against_ the rules,” isn’t good enough for Mr. Stupidly Picky.

Zack breaks up the monotony roughly around six o'clock, with an over-excited grin and probably way too much blind faith in their abilities, to lead them over to the tunnels. Andre and Wanda refused to show their faces all day, but Lydia hangs back to see them off, with an intentional look of faux disinterest pasted over her expression. Her mouth twitches a little bit when Zack kisses her goodbye, and Dean can’t help his small smile at the subtle display. It’s kind of cute actually, seeing that the Ice Queen actually has a heart underneath all that pretension. Zack gives his girlfriend one last click of his tongue, then flits off to wherever he’s decided to lead them, his ragged hair wafting behind him. Dean passes the knife to Sam—his brother’s better at maneuvering with the added tail, which makes Dean the bait—and the three of them quickly make their way over to the mysterious cave tunnels that Zack keeps going on about.

They reach the mouth of the cavern just as it starts to get dark, grainy light painting everything a dull gray again, but Zack hesitates at the tunnel entrance. “Okay, dudes,” he says, a little nervously. “So I was thinking, like, this is as far as I should probably go. Y’know?”

Dean lifts a skeptical eyebrow. “I thought you said you wanted to help?”

“Well yeah, man. I led you here.” Zack shifts in place, uncomfortable. “That’s helping, right?”

Dean lets out a noise of sharp disbelief, but Sam places a calming hand on his shoulder. “Thank you,” his brother says gently. “You’ve done more than enough.” Dean opens his mouth to make a sarcastic comment, but Sam digs his fingers in harder, cutting him off. “We can handle it from here.”

Zack practically melts in relief and throws Sam a grateful grin. “Yeah, man. It’s just—I’ve got a shoal to look after, y’know? Shouldn’t go throwing myself into total, whacked-out danger when you guys are the pros here.”

“Yeah, of course,” Dean says sarcastically.

“Awesome, man,” Zack says, clapping a hand onto Dean’s other shoulder. “Thanks for understanding.” He gives them both one last grin, then jets off back the way they came. “Good luck, dudes,” he calls back over his shoulder, his outline eventually disappearing into the murky water.

They watch Zack swim away for a minute or two, and then Sam turns to him and says, “I should go in there with you.”

“Dude. No.” Dean squeezes Sam’s fingers, then calmly moves them away.

“I’m serious, Dean. Your plan was for the three of us.”

“Yeah? Well, now I’m changing it. I’m allowed to, ‘cause I was the one who came up with it.”

His brother gets that familiar stubborn look on his face. “You’ve got no back-up with Zack gone. How am I supposed to know if you’re alright or not?”

“It’s the same plan, Sam,” Dean says. “I’ll go lead Aquaman out this way, and then you shiv him the second I swim past.”

Sam scoffs. “Yeah? And what if the asshole nabs you?” He shakes his head, lips tight with worry. “Zack was supposed to tail you and make it back to me if anything went wrong. I’m gonna have no way of telling whether you’re okay or not if I’m stuck out here.”

Dean sighs and rubs at his eye. “You got a better idea, then?”

The pinched cast to Sam’s face makes it clear that he doesn’t. “At least take the knife,” he offers.

Dean flaps a hand at the mouth of the tunnel. “It’s too fucking narrow in there, man. No room to fight. It’ll be way more useful out here with you.”

“Dean, I don’t like this,” Sam says quietly. He gazes at Dean, doleful puppy eyes at full blast. “What if something goes wrong?”

“Then, we’ll improvise,” Dean says reassuringly. “Just give me ten minutes or so, okay? After that, you can feel free to come charging in to my rescue.”

His brother lets out an amused spray of bubbles, despite himself. “You get yourself killed by a fucking mermaid and I am never gonna let you hear the end of it. You understand me?”

“Yeah, okay,” Dean grins. “That sounds fair.” He flicks at Sam’s collarbone and wiggles his eyebrows a little. “So…you gonna wish me luck or what?”

Sam rolls his eyes in exasperation, but can’t quite hide his affectionate smile at the obvious prompting. He gives Dean a quick kiss, but the closed-mouth nature of it makes it clear that he’s still worried. “Good luck,” Sam says against his lips, then he shoves at him with his free hand. “Alright, fucking go already.” The fake irritation doesn’t ring true in the slightest, but Dean pretends to give in anyway. He tosses his brother a final wink, and swims into the dark caverns.

He hadn’t been lying to Sam, the tunnels are fucking _narrow_ , and if Dean’s distaste for heights had tended a little more toward enclosed spaces, there’s no way he would’ve been able to even make it this far. It’s dim as fuck between the confining walls, and Dean can just barely make out the twists and turns ahead of him. It's kinda like being in a completely dark room when your eyes have almost adjusted, but aren't quite there yet. All he can make out is flashes of shapes in his peripheral. Dean stretches his arms out to either side and his fingertips just brush the rock around him. He’s got breathing room at least (or drinking room, or whatever the fuck you call it when you’ve got stupid gills instead of lungs), so it shouldn’t be too hard to stay ahead of the nix when they both come back this way. Dean catches the barest shimmer out of the corner of his eye, probably some dumb fish or something swimming past, and ignores the animal to focus back on the caverns. Dean squints at what he thinks might be a slight curve in the tunnel ahead of him—

And then everything goes black.

 

~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~

 

Dean comes to slowly, with a head full of roiling mush and a dull twinge in both of his arms. _It’s brighter in here—_ is the first clear thought to roll across his brain. Quickly followed by _—Where the fuck is here, anyway?_

“Ah, you’re awake. How lovely.”

Dean snaps his head up at the unexpected voice, and then groans in pain as the sudden movement sends his eyes spinning in his skull. The rough bite of rope he can feel digging into each wrist explains the aching arms at least.

“Yes, I’m sorry about that,” the silken voice continues on. “It was just a small tap on the head, you see. But I couldn’t risk you struggling on the way over here.”

Dean manages to fix his bleary gaze on the figure in front of him, blinking until whoever’s speaking slowly comes into focus. It’s a man—or it looks like a man at least—with bright, golden hair and eyes the same shade as the water around them. Too blue to be human. He’s surprisingly pretty for a dude, but Dean’s had that same comment leveled at him far too many times to be anywhere near comfortable with the thought. 

“So where is here, exactly?” Dean grates past his gummy throat. It looks like some kind of underground grotto, huge and clear compared to the tunnels from before, and Dean guesses that this must be the guy’s main base of operations. He tugs at the ropes around his wrists once more—they’re annoyingly thick, some kind of hemp fishing net or something—and fixes his glare back on the man in front of him. “I’m gonna go ahead and assume that you’re the nix I’ve been looking for.”

The man chuckles, voice light and airy despite the water surrounding them, and crosses his legs. He’s completely nude, and apparently completely unbothered by his state of undress, given his casual lounging. He’s relaxing atop one of the towering rock plateaus springing up from around the vast cave, but he appears to be sitting rather than floating. Like the water’s buoyancy doesn’t have any effect on him. “What is your name?” he asks courteously, cocking his head to fix Dean with an affable smile.

“How about you tell me yours first?” Dean grits through a much less authentic smile of his own. He doubts that Sam’s theory about defeating nixes with names holds much water, but it’s worth a shot given his current situation.

The nix lets out another airy laugh and scoots forward along his rocky perch, fixing Dean with a full-blown grin. “You know your lore,” he says. “I’m suitably impressed. But you can’t think it would be that simple?”

Dean shrugs and twists his wrists against the thick knots. “Can’t blame a guy for trying, right?”

“I wouldn’t dream of it,” the nix hums. He seems perfectly content to just sit there and quietly stare at him, and Dean clears his throat awkwardly.

“So,” he says, attempting casual conversation. “This whole BDSM get-up, that just for kicks or what?”

The nix laces his fingers over his knee and fixes Dean with a soft look. “I must make sure my wives are docile before I bring them to their new home.”

Dean’s jaw drops at the guy’s sheer audacity. “No. No way. Are you fucking _kidding_ me?” He tugs at his restraints in helpless frustration. “No! I am not your goddamn _wife!”_

“Why, of course you are,” the nix coos. Like Dean’s just being fucking _coy_ or something. “I have chosen you as my beloved.” He grins again. “You should count yourself lucky. I’ve never had a Mer before. Of course, I’ve never had the good fortune to encounter a Mer as beautiful as you are.”

Dean’s eye twitches and he purposefully ignores the nix’s _compliment_ , for the sake of his own sanity. “So, what?” he bites out. “You infected me with your love potion shit while I was out cold? ‘Cause I hate to break it to you, pal, but you might’ve fucked up somewhere along the line. You ain’t exactly my type.”

“I am not a siren,” the nix says, pleasantly amused, “though I suppose we are related. My song is of a more… _literal_ kind.”

“What, like ‘Freebird’?”

“Nothing that _gauche_ ,” he laughs. Then he sighs and gazes off into the middle distance, lost in his memories. “Women used to come for miles just to hear the strains of my melodies. And I would teach men to play the strings themselves.” He tilts his head back at Dean, excited. “Do you play?”

Dean tosses him a bloodless smile. “Took guitar for a hot second when I was a kid. Turns out I’m shit at it.”

The nix hums. “Disappointing. Perhaps I could teach you.” He trails a hand through the water between them, currents winding over his fingers. “Finding wives used to be so simple back then. They all practically threw themselves at me. And now, with all this—what do you call it? ‘Stranger Danger’? It’s all gotten so… _complicated_.”

“Yeah,” Dean says dryly. “The 21st century’s a bitch.” Then he stills as something in the nix’s statement rubs him the wrong way. “Wait. You did say  _wives,_ right? As in, more than one?”

“Of course. You can’t expect a specimen like myself to remain content with just one beloved?”

“ _Right_ ,” Dean says, tone like acid. “Of _course_.” He cocks his head back toward the tunnel entrance and raises an eyebrow. “So, where are the others then? The ones you took from the beach.” Dean mentally scrolls through what he can remember from the victim list. “One of them was a…Jenny-something. Dark hair. Early forties.”

“Ah, yes,” the nix sighs. “Jennifer.” He gazes off with a wistful little grin. “She was so beautiful. And so entertaining.”

“So where is she now?” Dean asks with a growing sense of trepidation.

“Well. Let’s just say that she stopped being so entertaining. The humans don’t last very long once I get them underwater, you know,” he says conversationally.

Dean swallows silently. “And then?”

“And then I had no more use for her.” The nix’s eyes flash as his grin turns predatory. “And I do get _so_ hungry.” Then his expression melts back into pure tenderness at Dean’s obvious anger. “But _you_ ,” he says, with a shallow attempt at reassurance, “you seem much more interesting. I think I could entertain myself with you for a very long time.”

“Yeah?” Dean asks bitterly. “And what is that compared to the typical shelf life here? Week, week and a half?”

The nix shrugs coyly. “A week can be an eternity when you’re in love.”

Dean can’t help the automatic eye roll. “Yeah, well, an _hour_ can be an eternity when he won’t shut up about the ethical rights of animal testing or some shit.”

“I don’t understand.”

Dean struggles against his ropes for another moment, then flops back against the rock wall with a grunt. “Time flies when you’re having fun,” he explains tersely. “Opposite is also true. That’s Einstein.”

The nix chuckles and moves closer to Dean.  _Instantaneously_. He’s up at his rock one moment, and then down by Dean the next, without even lifting a finger. And that must be how the nix got the drop on him back in those tunnels. He shifts _through_ the actual fucking water. “I’m not sure that is the correct principle,” he says, clearly amused. “But my, are you fascinating.” He trails a hand down the side of Dean’s face, steady and gentle, despite Dean’s attempts to twist away from the lingering touch. “I am so pleased to have taken you,” the nix purrs. Then he suddenly freezes rigid, shoulders up around his ears. “You are not welcome here,” he spits. And Dean gets weirdly insulted, considering the guy had spent all the effort to bring him here against his will in the first place—until he realizes that the nix isn’t talking to him at all. He spins around, not a single, golden hair out of place, and flashes back up to his rock tower, glaring at a figure huddled by the cave mouth. “Come out where I can see you, Mer,” the nix says threateningly. “You’ve already interrupted my wife and I. And it’s rude to lurk in doorways.”

There’s a flash of red as the figure swims out into the light, and Dean wants to simultaneously jump for joy and bang his head against the wall at the sight of his brother—who is now vulnerable and a clear target, out in the open water.

“I think you have something of mine,” Sam says confidently, his voice carrying clear across the grotto. “And I’d like him back.”

The nix’s lips twitch at Sam’s surety, and he spares a glance back at Dean. “Is he your mate?” he asks Sam calmly.

“Sam,” Dean growls, catching his brother’s attention. “If you say yes, I will _murder_ you.”

“Uh,” Sam blinks. “He’s my brother.”

“Then you have no claim.” The nix settles back on his heels and waves a dismissive hand across the cave. “I’m feeling charitable at the moment, so you may leave with your life. You will not receive this offer a second time.”

“Claim?” Sam glances back at Dean, and he can see the wheels in his brother’s head start to turn. Those stupid fucking wheels. “What if I do have a claim?” he asks carefully. “If we are, uh— _mated?”_ Sam winces slightly on the last word, and Dean groans low in his throat, taking whatever hint of solace he can from that, at least.

The nix narrows his stare and rises to his full height again, making himself look larger. Pure, bestial instinct. “You must be the one he mentioned, yes? His ‘animal testing’ one?”

“Uh, I don’t…” Sam turns to squint at Dean over the nix’s shoulder. “ _What?”_ he asks, completely confused.

Dean lifts his shoulders into a shrug. “I have no idea what he’s talking about,” he says, as innocently as he can get away with.

“Um…sure,” Sam says hesitantly, turning back to the nix. “Yes. I guess.”

“Sam,” Dean sighs, thumping his head back against the rock. “ _Goddammit_.”

The nix’s back tenses in anger as he glares at Sam. “Then I suppose I will have to eradicate this prior claim,” he says darkly. “It’s only proper, after all.”

“Sure, of course,” Dean snits. “Can’t go around snatching people _improperly_. What would the neighbors think?”

“You will submit to me after I kill your mate,” the nix says stiffly, not even turning to look at Dean. “It’s why you were resistant before.”

“I’m _resistant_ ‘cause you’re a rapey dick. And I doubt that’s gonna change in this lifetime.”

“ _Enough_ , beloved,” the nix snarls. “You do not want me angry with you.” He turns back to Sam, completely deaf to Dean’s continuing jibes, and raises a formal hand. “Will you fight for your mate, Mer?” he calls out. “Or do you forfeit your claim?”

Dean can see Sam’s entire body tense even from all the way across the grotto. “Whenever you’re ready,” he spits.

“As you wish,” the nix says grimly. He jerks his mouth wide open and sharp, needled teeth sprout out of his unhinging jaw, like one of those freaky, deep-sea fish that never see the light of day. Sam starts a little at the disturbing display, and then the nix flashes out again, disappearing in a glint of light.

“Sam!” Dean shouts across the cave. “The dude fucking _teleports!_  Like Nightcrawler!”

“What?!” Sam stares at him, agape. “Are you serious?”

“No, of course not!” he snaps sarcastically. “I’m just fucking with you for the hell of it!”

Sam whips his head around, tail twitching nervously as he tries to keep his eyes on the entire 360. “How am I supposed to fight a monster that can pop up anywhere?” he calls back.

“I dunno!” Dean snarls, yanking at his ropes until his shoulder twinges. “Maybe don’t get caught in the first place?”

“That’s pretty rich coming from you, Dean!” The nix chooses that moment to flash back up behind his brother’s left shoulder, and lunges forward, teeth bared.

“Sam! Seven o’clock!”

Sam lashes out with the knife in a wide arc, just barely missing skin, but leaving himself wide open for a second attack from the other side. The nix pops up again before Dean can call out a warning, and he takes a solid gash out of Sam’s right bicep. His brother grunts in pain, but stabs out wildly, managing to nick the fucker with the tip of the bronze blade. There’s a hiss of sizzling flesh, and then he disappears again.

“Sammy, are you alright?” Dean shouts, frantic.

“I’m fine. Shut up!” Sam swings the knife again, but doesn’t hit anything other than his own paranoia.

Dean growls at his own uselessness while tied up like this and lets his body sag against his ropes, fins drooping against the rocky shelf beneath him. _Against_ the shelf. Why the fuck didn’t he notice that before? Dean snaps his head down and scans over whatever’s in reach. Sam lets out another pained cry from across the grotto, but it doesn’t sound too serious, and there’s another hiss of bronze against flesh, so Dean keeps his focus on the task at hand. There are a few sharp pieces littered atop the silt, but there’s only one rock within reach, so that’ll have to do. Dean stretches out with his stupid, unwieldy tail and manages to scoot it closer. He gets it balanced on one of his fins and tosses it up as best he can, angling and fanning it up through the water until he can close his right hand around the jagged stone. Dean barks out a laugh and starts sawing at the ropes around his wrist. “Eat your heart out, Macguyver,” he crows to himself.

The rope fibers fray under his continued assault until he finally gets them weak enough to snap with a solid yank. Dean glances up to check on Sam, but his brother seems to be doing alright. There are a few red lines scoring his arms and chest, but nothing life-threatening, and the periodic sizzling sounds make it clear that he’s at least holding his own. Dean grins at their combined successes and starts in on his left wrist, slashing at the knots until they start to give.

“Do you _wish_ me to be angry with you?” Dean jumps as the nix suddenly appears right in front of him, forcefully snatching his improvised weapon out of his fingers and curling his own hand around Dean’s throat. Dean scrabbles at the grip with his free hand, but the nix’s supernatural strength holds out. “If you continue to irk me,” he snarls through needled teeth, “I shall not hesitate to devour every last bit of you.” The nix tightens his grip, one final warning. “So do not displease me. _Beloved_.” He finally lets go of Dean’s throat, blinking out again and leaving Dean coughing at the rough treatment. He can breathe fine—turns out gills are good for something after all—but it still hurts like a motherfucker.

The nix flashes back to his brother again, apparently invigorated after his little _strangle_ , and manages to get a good sideswipe in, leaving Sam hissing in pain. Dean pulls at the ropes he’d managed to start on, but the netting isn’t shredded enough to give, and he just has to hope that Sam can handle the fucker.

“Y’know,” his brother calls out, whipping the knife in front of him. “It’s not very sportsmanlike to hide like this.” He tries for a cocky grin, but it ends up looking more exhausted than anything else. “I’m not even sure this counts as a proper duel, considering what a _coward_ you are.” One portion of the water shimmers for a bit, but the nix stays hidden. Sam chuckles at the reaction and continues his taunting. “I mean, I really doubt Dean will accept you as his mate if you had to win through such underhanded means.”

Dean catches Sam’s drift and jumps in. “Oh, fuck yeah!” he shouts. “No way I’d be interested unless you won in a fair fight! Rules of Engagement, asshole!”

And that seems to do it. The nix flickers into view again, heading directly for Sam, but visible at least, and his brother grimaces as the monster swims right at him. Sam lifts the knife up in front of him and holds his position as the nix reaches out to claw at his chest. Dean can see his brother surge forward, moving to plunge the blade between the freak’s ribs—and he can see the nix’s fingers close around the necklace resting on Sam’s chest, pulling at the exact same time.

_“Sam, don’t!”_

Sam shoves his arm forward and slides the knife into flesh just as the nix yanks the amulet from his neck, crushing the shell between his fingers.

The nix lets out a final scream as the bronze finds its way home, sizzling and bubbling the flesh around the wound until he completely dissolves into the water, leaving nothing but a scattering of teeth behind. They don’t make any noise as they slowly settle to the floor of the cavern.

“Heh,” Sam laughs exhaustedly, letting the knife drift from his nerveless fingers. “He called you his wife, man.”

“ _Sam_ —”

“Yeah, yeah. I know.” He rolls his eyes amicably. “You’re way too manly and impressive.”

“Sam, shut up! Your _necklace_.”

“What?” Sam’s eyes go wide as he reaches up to feel for the string at his collar, and the blood drains from his face the instant his fingers hit bare skin. He shares a terrified look with Dean, then flips his tail out behind him, gunning across the grotto as fast as he can, expression wracked with intense determination.

“C’mon, Sammy.” Dean swims out as far as his restraints will let him and reaches out with his right hand, twitching his outstretched fingers. “You can do it. C’mere.”

Sam sets his jaw and puts on a burst of speed, then flips over with a pained groan as the transformation begins to hit him. He tries to straighten himself out and swim closer, but falters again, only two-thirds of the way across. “Shit, Dean,” he groans through clenched teeth. “I’m sorry. I’m so sorry.”

Dean tears at the remaining tie around his wrist, muscles straining as he pulls against the rough hemp. But it’s fucking _impossible_ with the water all around him. There’s no leverage. And all of his yanking isn’t gonna do anything but dislocate his shoulder. Dean risks a glance back toward his brother. Sam’s got one arm curled around his ribs and he’s grimacing through another wave of pain. The gills were the first thing to show up, and they’ll be the first to go. And his little brother is gonna fucking _drown_ in front of his eyes if Dean can’t get there in the next few seconds.  _Leverage_. Fuck, that’s it. Dean twists around and shoves his tail against the rock wall now in front of him. The craggy stone rips at his thin skin, but he pushes as hard as he can through the pain, pulling with his upper body at the same time. “C’mon, you motherfucker,” he spits at the tattered netting. The rough stone scrapes off the entire first layer of scales and steeps the water around him in his own blood, but he doesn’t let up until the rope finally frays and snaps.

“ _Dean_ ,” Sam gurgles wetly from behind him, but his name comes out muffled. Lost amid the last breath of air that bubbles out of his brother’s lungs.

Dean flings himself out toward the open water, ignoring the salt stinging against the raw patch of his tail, and makes it to Sam just as his shoulders start to tremble. He clamps a hand around the back of Sam’s neck, yanks him forward, and crushes their lips together, exhaling as much air as he physically can into his brother’s mouth. Sam’s chest stutters and rises against his own, and Dean lets out a relieved sob at the motion, clutching his brother to him with a bruising grip.

Of course, Sam immediately wastes all the air Dean’s just given him, letting out another stream of bubbles that might be, “I’m sorry,” but it’s almost impossible to tell.

“I gotcha, sweetheart,” Dean says, wrapping his arms tighter around Sam’s back and breathing more oxygen into his lungs. “I gotcha. You’re gonna be fine.” He takes a moment to come down from the aborted terror of the last few minutes, closing his eyes and pressing his forehead against his brother’s jaw, until he can finally manage to pull himself together. Then he shifts away so that he can heft Sam’s left arm over his shoulder, curling his own around Sam’s waist in return. “Alright, c’mon, you lazy bastard.” Sam’s shoulders jerk in what might be a laugh, but it immediately turns into a spasm with the next wave of pain. Dean catches his gaze with an apologetic one of his own. “Sam, your ass is fucking heavy. And I’m gonna need you to help me swim as long as you can. Okay?” His brother nods and moves his tail weakly, trying to cooperate through the fucked-up spell wracking his body. “Perfect,” Dean says softly. “Thank you.” He pats at Sam’s fingers on his shoulder. “Just tap me when you need more air, okay?” Sam nods again, and they both make their way toward the entrance of the grotto.

He and Sam fall into a workable rhythm, steadily eating up the distance before them and only pausing when Dean needs to breathe for his brother. They get all the way to the mouth of the cave before Sam doubles over again with a wet cry, clutching at Dean’s deltoid like it’s the only thing keeping him from floating away. His eyes slam shut in pain, and Dean can’t do anything but hold onto Sam as his tail splits in two, slowly ripping apart from the bottom up. Dean jerks his head away from the gruesome sight and starts them moving again, soldiering past his brother’s hurt twitching as he takes them back into the cave tunnels. He swallows hard, and tries not to think about how lucky he was that he didn’t have to catch the play-by-play the first time around. Because that’s an image that’s gonna haunt him for a while yet, and he can’t imagine it was any better in reverse.

Dean rockets them through the twisted corridors, keeping Sam tightly tucked against him so that he’s not scraping against the narrow walls, and sends up a silent message of gratitude that the bay isn’t deep enough that they have to worry about Sam getting the bends. And Sam, for his part, is getting closer to his actual self with each passing minute. The changes seemed to speed up once the big stuff was out of the way, and now he’s a solid weight against Dean’s side. Heavier and broader again, his cock soft against Dean’s hip. The gun callous on the tip of his trigger finger is back too—less defined than the one on his right—but it still catches and drags against the stupidly delicate skin of Dean’s back. He can even feel the light brush of his brother’s leg hair whenever his shin thumps against the upstroke of his tail.

Sam suddenly lets out a flurry of bubbles that might be Dean’s name, and digs his fingers into the meat of his shoulder.

“I can’t hear you, kiddo,” he says distractedly, trying to focus on getting them through the caverns. “Just hold your breath, okay?” Sam shudders again, and Dean can’t help but glance over to see what’s got his brother so worked up.

He looks anxious—he’s blinking too rapidly at the walls around them and his fingers are a little too tight around Dean’s arm. Sam flicks his eyes over in the vague direction of Dean’s face, and there’s no accompanying shine. And Dean suddenly realizes that he can’t see.

“Shit,” he breathes, pulling Sam in closer against his side. “It’s okay, Sammy. I’ve got this.” Dean sweeps a comforting thumb over his brother’s waist. “You just gotta trust me, okay?”

Sam taps at his fingers, and when Dean stretches up for another breath, it’s more tender than the passing of oxygen needs to be, and Sam silently nods against his mouth. Dean presses a follow-up kiss to his brother’s closed lips, and then swims faster.

They finally make it through the never-ending tunnels and out into the bay, and Dean surges up toward the surface the instant they’re free, straining for real air. Sam’s fingernails bite into his skin at the speed, but he doesn’t let up, crashing them up and past the breaking waves until they’re both back under the cloudy Maine sky.

“Are you alright?” Dean growls the instant they’re topside, grabbing at the sides of his brother’s face. “Sam, answer me, dammit! Are you okay?”

“Yeah, I’m fine,” Sam coughs roughly. Then he gulps in another breath of actual air and sags against Dean’s hold. “I’m good.” Sam looks like a drowned rat with his hair dark and slicked to his skull and Dean knows that he can’t look much better himself, considering his own is plastered down over his forehead, all of the product completely washed out. 

“Don’t fucking do that again, you asshole!” Dean barks, punching Sam as hard as he can in the arm that isn’t bleeding.

But Sam just smiles weakly in response. “Thank you,” he says quietly, and Dean finally lets all of the terrified adrenaline drain away.

His entire body slumps in relief and he throws his arms back around Sam’s shoulders, crushing himself against his brother’s chest. “ _Jesus Christ,_ Sammy. You’re gonna give me a damn heart attack. You can’t do that shit to me.” Dean clings to his brother for a few moments more before he finally feels stable enough to pull away. “You know,” he jokes weakly, “this whole rescue thing is starting to get a little old. Maybe you should consider pulling your weight once in a while.”

“Oh, f-fuck you, man,” Sam says, shivering. “I’m the one who ganked the nix. So you’re welcome, asshole.”

Dean mentally chastises himself for his obliviousness and ineffectively rubs his hands over his brother’s arms. “Shit, Sam. I’m sorry.” He’d totally forgot about the completely reasonable human reaction to cold in the wake of all his terror. “Here, hold on.” Dean wraps an arm around Sam’s waist again and aims them toward the shoreline. “Think of something warm, okay?” he says, glancing over to make sure Sam isn’t hypothermic yet. “Hey, remember that time back in Florida when the motel A/C broke?”

“Y-you mean Lakeland?” Sam asks through chattering teeth. “When we were hunting that demon?”

“That’s the one. And I made us stay in the room the whole time, remember? ‘Cause I thought she was outside.” He pulls Sam tighter in against him as he struggles toward the shore. “What was it, like ninety-eight degrees in the shade?” Sam nods his head jerkily and lets out a too-sharp laugh. “Yeah, that’s right,” Dean says. “And like eighty percent humidity.” 

“G-god, that was awful. Thought I was gonna puke.”

“Yeah,” Dean prompts, trying to get Sam to think about absolutely anything other than cold water. “And you took all your fucking clothes off. Strutting around like the world’s biggest cocktease.” 

“Fuck you,” Sam laughs shakily. “I was trying _not_ to die of heat stroke.”

Dean presses a quick kiss to the side of his brother’s neck, more to distract him than anything else. “Took every shred of willpower I had not to jump your bones then and there,” he says quietly.

Sam shivers violently against his side. “You should have.”

“Yeah, don’t I know it.” Dean grins. “Woulda saved us some time, huh?”

Sam throws him a tight smile in response, but doesn’t say anything else. Apparently, he’s conserving as much body heat as he can for just shuddering miserably, despite Dean’s continuing attempts at distraction. Sam eventually lets his head droop down, resting his forehead against Dean’s temple, and spends all his remaining energy on clinging to Dean’s side while he lets him do all the work of getting them both back to shore. Dean would be a little more irritated if it wasn’t par for the course. He says something out loud to that effect, but his brother only gives him a too-quiet hum in reply.

Dean finally makes it back to the section of beach they’d started at, only having to make a few course adjustments on the way, and shoves Sam out of the water as best he can from his position behind the breaking waves. He doesn’t have the leverage to hoist him and his brother out of the ocean at the same time, so the guy who’s freezing to death comes first. “C’mon, you lazy bitch,” Dean grumbles, grappling with his brother’s trembling limbs. “Get your ass onto dry land, Sammy.”

“D-dean,” Sam mumbles, stretching an arm back out. “C’mere.”

“Go get your clothes, Sam.”

Sam shakes his head like the stubborn ox he is, spattering Dean with icy droplets from the wet ends of his hair. “It’s gonna hurt, Dean. You gotta come here.” He leans back out over the drop-off and wraps a shaking hand around Dean’s arm. “C’mon, I don’t wanna get my c-clothes wet. Let’s just fix you first.”

Dean sighs and lets his brother clumsily drag him up onto the sand. “You’re gonna freeze solid, dude. Get dressed. I’ll be fine.” Sam stumbles under the weight of his stupid, heavy fish tail, and Dean ineffectively tries to wriggle free. “Look, I promise I won’t mess up your precious fucking shirts. Just stand further away from the splash zone or whatever.”

“I’m not making you go through that shit alone,” Sam says determinedly.

“I’ll be _fine_ ,” he says again, rolling his eyes.

“No. You won’t.” Sam flicks his wet hair off of his face, then runs a frustrated hand over his forehead. “ _God_ , Dean. Would you just shut up and let me help you out for one freaking minute?”

“…Fine,” Dean grunts, relenting out of sheer annoyance.

Sam drops down onto the sand in exhausted victory, and then finishes hauling Dean up into his lap. He drapes his arms over Dean’s chest and Dean very charitably ignores the light tremors still running through his brother’s body. “You ready?” he asks.

“Yes, I’m ready,” Dean says irritably. The moonlight glints sickly off of the wet green and bronze of his scales, and Dean’s ready to suffer through any amount of physical discomfort as long as it means that he doesn’t have to look at the thing anymore. “Friggin’ drama queen. Just do it already.”

Sam snorts under his breath and curls his fingers around Dean’s necklace. “Okay,” he says. “Here we go. One, two, _three_.” He yanks at the thing like he’s ripping off a band-aid, and Dean cringes as the looped twine clears his head. 

At first, there’s nothing. Just the strain of the muscles Dean can’t help but tense in apprehension. Sam drops his forehead to rest against Dean’s hair, wrapping his arms a little tighter—and then Dean’s ribs start itching. He reaches down to rub at the sensation, but Sam’s grip on his wrists is unrelenting. His brother starts murmuring quiet apologies into the back of Dean’s head, keeping him squashed against his chest, and then the fire flares to life, racing up along his nerves. Dean hisses through his clenched jaw as the pain sweeps over his body, arching away from the sting, but Sam stays firm, still apologizing even as he holds Dean immobile. Dean lets out a long, pained groan and tries to curl away from the agony as best he can, jamming his head back against his brother’s bare shoulder.

“I told you,” Sam says softly, but he doesn’t sound happy about it.

“Shut up, Sam,” Dean growls, stiffening as another spike of pain rips through his legs. Or tail. Or _whatever_ —probably legs by now. He slams his eyes shut. Sam’s earlier horror show is still running through his brain, and he really doesn’t need to see it reenacted on something as personal as his own freaking body. And apparently, it’s pretty gruesome, because Sam lets out a hushed little choking noise and clenches his fingers harder around Dean’s wrists. “Fucking awful, right?” Dean pants through his teeth.

“You’re almost done.”

“Yeah, that’s comforting,” Dean grits out. Then he spasms as another wave of agony rockets over his upper body. After a few more minutes, the crests slowly start to abate, fading into little, stinging shocks, and Dean practically collapses in relief once the pain finally ebbs away.

“Hey. You okay? Talk to me, man.” Sam loosens his grip to shake him a little, as Dean blissfully savors the feeling of a world without pain.

He _feels_ human again—sturdier and more solid—but stretches his hands down to pat over his legs, just to make sure. And there they are, curving out of his hips just like they’re supposed to be. Dean moans in relief and runs a hand over his jaw, the reassuring rasp of stubble back where it belongs too. He lets out a final, elated, “Oh, thank god,” and falls back into Sam’s lap. 

Sam lets out a grateful breath of his own and presses a kiss to Dean’s damp hair. “You alright?” he asks.

Dean ignores him completely in favor of craning his neck down at his own lap. “Hey, buddy,” he sighs happily.

“Um…hey?” Sam sounds confused until he glances down at where Dean’s looking. Then he throws his hand up into the air with an exhausted sound. “Oh my god, you’re talking to your dick.”

“’Course I’m talking to my dick,” Dean says patronizingly. “Poor guy missed me. Didn’t you boy?” he coos.

Sam scoffs deep in his throat, running his fingertips over the unbroken skin of Dean’s sides. “Well, sorry to interrupt your _moment_ or whatever, but we should probably get going.”

Dean hums and relaxes back into his brother’s gentle ministrations. “And why’s that?” he asks lethargically.

“’Cause we’re naked on a public beach?”

“They should name a cocktail after that.”

Sam lets out an amused snort and stills his hands. “Bit of a mouthful don’t you think?”

Dean can’t hold back the punch-drunk chuckle. He really tries. “That’s what she said.”

Sam doesn’t say anything for a long while, fingers resting lightly along Dean’s ribs, and eventually, Dean tilts his head up to see if he’d somehow offended his brother’s delicate sensibilities. But Sam is just holding Dean’s necklace in one hand, contemplatively staring at it under the dusky cloud cover.

“It’s pretty, I know,” Dean says, raising a solitary eyebrow. “But I’m not sure it goes with your coloring.”

“D’you think—” Sam lets out a breath, then gives his head an embarrassed shake. “Do you think we should keep it? Could come in handy.”

“How, in god’s name, could that thing ever _possibly_ come in handy?” Dean asks. He’s going for sarcastic, but he’s pretty sure his sentence comes out more aghast than anything else.

“I don’t know. What if we have to hunt another sea monster?”

Dean snorts, then pushes himself up and out of his brother’s arms. “If we ever have to hunt another sea monster, I’m renting a goddamn _boat_. With harpoons and shit.” He pins Sam with a look. “And guns. Lots and lots of guns.”

Sam concedes the point with a small smile. “Should we give it back to Zack then?”

“Fuck Zack.”

“Wow, Dean. Tell me how you really feel.”

“I’m serious, man.” Dean tugs the string out of Sam’s fingers. “I’m not letting a bunch of strung-out, hippie _fish_ jump any more people into their little gang. Plus, that Andre guy’s probably gonna shank the very next human he sees, just on principle.”

Sam nods his head in quiet acceptance, so Dean shakily pushes himself to his feet and drops the charm onto the packed sand. Then he brings his heel down hard, crushing the delicate shell underfoot. Sam jumps up to catch him the instant he starts to wobble, still trembling on his unused legs, and Dean grins. “There we go,” he says smugly. “Problem solved.” Although, not entirely, because they’re both still wet and freezing. And all it takes is one more full-body shiver from his brother, muscles twitching in the icy breeze, before Dean is reaching over to scoop Sam back against him. It’s not entirely selfless. Sam’s body heat, however damp, is still a warm buffer from the wind wherever their skin is pressed together.

“Alright, are you done?” Sam asks, hands twitching over Dean’s shoulder blades. “Clothes now? Please?”

Dean rubs his hands as vigorously as he can over his brother’s back, then steps far enough away that they can walk without tripping all over each other. “Okay,” he breathes. “C’mon, Sammy.” They stumble up the stretch of beach on numb extremities and Sam shudders again as he clutches at Dean’s waist. “You were right, you know,” Dean says teasingly. “I totally should have brought my jacket.”

Sam shoves at him in annoyance, and then quickly yanks him back in again when the space allows the cold air to come seeping through. “Fuck you,” he mutters grumpily, but curls up against him just the same.

They make their way to their super secret hiding place along the jetty and tug the salt-starched bundles of clothing out onto the sand. Dean tosses Sam’s t-shirt at his face to use as a towel and does the same with his own, and after a cursory and mostly ineffective rub-down, they yank the rest of their stuff over cold, damp skin.

“Y’know,” Dean says conversationally, while buttoning his shirt over his bare chest. “I still don’t understand how you were so damn calm about the whole thing. I was practically foaming at the mouth down there, but you were cool as a cucumber the whole time.” He laughs under his breath and adds, “Or more like a _sea_ cucumber, right?”

Sam doesn’t laugh at his hilarious joke. He just shrugs and puts on a terrible poker face, remaining suspiciously silent as he adjusts his rolled-up sleeves.

“...Oh my god,” Dean says incredulously. “You liked it.”

“What?” Sam looks exactly like he used to when he was eleven and Dad would catch him reading under the covers after lights out. “No, I didn’t.”

Dean makes a strangled noise and tries to reign in the surge of excitement. If he’s right, then he’s got sibling fodder for the next few _months_. At least. “Jesus Christ, dude. You did. You liked being a _mermaid_. You thought it was fun.”

“Shut up,” Sam snaps, but his cheeks burn red. “No, I didn’t.” He yanks his handgun out of the sand and sulkily jams it into the back of his jeans, striding up the beach with his stupidly long legs and leaving Dean in his dust.

“It’s okay, Sammy!” Dean calls after his brother’s retreating back. “No shame in wanting to be a pretty mermaid!”

Sam refuses to speak to him for the entire car ride back to the motel. 

 

~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~

  

Luckily for Dean, Cape Elizabeth is a fairly smallish town for a tourist trap and the ‘Beach Inn’ is only a ten minute drive inland. The roads are winding, but cleanly paved—the county’s tax dollars at work—and lead them past long stretches of homey suburbia on either side. Every porch light they speed by twinkles cheerily through the overcast night, and Dean’s nose twitches at the overbearing quaintness of it all. The cutesy landscape isn’t any easier to stomach than it was on the way in, and Dean doesn’t know why he assumed he'd have built up a resistance by the second time through. 

He spins Baby up into the Inn’s designated lot with a faint squeak of rubber and then kills the engine, sneaking a glance at the passenger seat out of the corner of his eye. Sam still appears to be subtly nursing his wounded pride or something, but Dean squeezes a hand over his brother’s thigh and gets a slight smile for his efforts. Or maybe Sam’s just too cold to hold a grudge right now. They grab their wet undershirts out of the backseat and shuffle up onto the porch of the colonial style façade. The woman manning the lobby desk doesn’t give them (or the sand they’re tracking in) a second glance, so they make it up to their room with a minimum amount of drama.

The ‘Ocean Suite’ they’re staying in is tiny—even by their standards—and more expensive too, given its proximity to the beach they’d needed, smack dab in the middle of Maine’s stupid vacation season. And Dean hates every inch of it. The place is covered in pastel yellow wallpaper with little starfish dotted all over it, and there are framed pictures of lighthouses atop each piece of wicker furniture. The curtains are thick and floral, and look like somebody’s grandma quilted them by hand—and the cheesy, ruffled look to everything kind of makes Dean want to run screaming. Exactly the same way it had this morning. He leaves the light off. The faded moonlight drifting in through the uncovered window is bright enough to see by and the hideous décor really doesn’t need the help.

Dean makes a beeline for the modest bathroom, intent on scrubbing the remaining salt and sand off of his skin, by force if necessary, while Sam simply strips right there in the middle of the room, leaving his clothes in a sandy heap, and then quickly burrows under the lacy, white covers of the nearest bed. Dean hits the thermostat on his way by, generously making sure that his brother won’t be a solid block of ice by the time he gets out of the shower. He’d offer to share, but the stall is ridiculously tiny and Dean ain’t _that_ generous. 

The bathroom is thankfully of a more subtle design, and only slightly less claustrophobic than the rest of the place. Dean thinks that’s due more to the lack of any cartoon starfish than actual square footage. “By the way,” he calls through the open door, twisting the knob on the shower until hot water crashes against the ceramic tile. “You gonna let me look at those cuts before they get infected?” Steam quickly fogs up the tiny room and Dean stretches out a hand to test the temperature. He tends to prefer his water hot enough to boil a lobster. Sam makes some sort of reply from the other suite, but his voice is muffled beneath the layers of blankets. “Can’t hear you, sweetheart,” Dean calls back.

“I _said_ ,” Sam repeats, voice clear enough that his head must be above the covers, “that I’m fine.”

Dean peels the stiff layers off of his body and tosses them into the corner, then steps into the pristinely white tub. “Yeah, sure,” he says through the glorious water pressure—one of the benefits to a more expensive hotel, at least. “You’ll be fine right up until the bit where your arms fall off.”

“Pretty sure leprosy isn’t an ocean-borne illness,” Sam snarks from the other room.

“I was talking about gangrene, you dick.”

“Sexy.”

Dean lathers up a hand and scrubs it through his hair until he can’t smell seaweed anymore. “I’m serious, Sam.”

“Yeah, well, I’m cold,” Sam grumbles, his voice muffled by the covers again. “I’ll do it tomorrow.”

“Sure,” Dean says, liberally dousing himself in soap bubbles. “Right after all the early bird gangrene has already unpacked and set up shop.”

Sam lets out an amused scoff, and then there’s a muted thud of something soft hitting the wall. “It’s necrosis, Dean. Not a job fair.”

“Yeah? Well, tell that to the gangrene.” Dean rinses off, and then greedily stands under the spray for an entire minute after he’s already clean. Purely because the hotel’s fancy water heater can probably take it. It’s a rarely experienced luxury he’s determined to take advantage of. Dean eventually shuts off the tap with a reluctant sigh and gingerly steps back out into the cooler air. “Where’d you put the first aid stuff?” he asks, grabbing one of the thick towels from the bar bolted into the wall. Sam doesn’t answer him as he dries off, so Dean steps into the main room and rests a hip against the doorway. “You ignoring me or you asleep?”

The giant lump under the covers of the bed closest to the door makes a noncommittal sound, and then a hand slips out to give a listless wave to where Sam had dumped his backpack in the corner yesterday.

Dean slings his towel around his shoulders and steps over to the lopsided pile of their bags. The room’s temperature is bearable enough now, due to the heater and the steam from Dean’s shower, that Sam’s refusal to move is probably more out of laziness than actual cold. He grabs their kit and walks over to where Sam is huddled, making a slight detour to toss the pillow Sam had thrown at him back on the bed. “C’mon, Sammy,” Dean croons sarcastically. “Up and at ‘em.” He yanks the comforter away from his brother’s body and then drops his used towel onto Sam’s face, scrubbing it over his head until Sam starts making sputtering noises and threatening to kill him.

“God, _fine_. Alright.” Sam rips the towel off and flings it away from the bed. “Fuck.”

Dean just grins in response. “Alright, lemme see,” he says, maneuvering an unwilling Sam into place. He clicks the bedside lamp on—the stand is carved into a obnoxiously cheery seashell—and examines what he’s working with in the muted lighting. Luckily, the cuts are shallow and there really aren’t too many of them, a few, faint lines of red crisscrossing his chest and arms. Sam was probably right about being fine earlier. The pissy expression on his brother’s face makes it very clear that he’s aware of that fact. “Shaddup,” Dean grumbles good-naturedly, then he reaches into the kit for a wet-nap. The scrapes are so thin that Sam’s not even going to need disinfecting, but cleaning them out can’t hurt. He runs the towelette over his brother’s clammy skin, and Sam’s pec twitches at the unexpected chill. Dean glances up to catch his brother’s eyes, his face thrown into stark relief by the sharp shadows, and not-so-accidentally sweeps the wet wipe over a nipple. Sam’s pupils dilate, but he doesn’t break the gaze, and Dean smirks to himself as he goes back to actually washing off most of the dried blood.

“What about these?” Sam asks softly, brushing his fingers over the rope burn on Dean’s wrists.

“They’re clean.” Dean finishes up and tosses the used wipe into the wastebasket. “I’ve had worse.”

“Your knees are fucked up too, man.”

Dean glances down at himself. The injuries he’d sustained from his tail’s grudge match with the rock wall must have made the transition along with the rest of him. It’s not bad though. It kinda just looks like he’d taken a dive over some asphalt. “Yeah, well I already took a shower. It’s as good as they’re gonna get.”

Sam slowly pushes himself up to sitting now that the requisite check-up is over and leans forward, lips not quite brushing Dean’s cheekbone. “Y’know, I think I promised you something earlier,” he says, voice low.

“Yeah?” Dean prompts, just as breathy. “And what would that be?”

Sam hums sinfully and ducks his head down to entice Dean into a slow, but heated kiss. Sam tastes like salt—brackish where Dean’s tongue meets his lips—but underneath is the familiar flavor of his skin. Dean chases it until his brother pushes him away. “Let me jog your memory,” he whispers, hot and wicked, and then slips down to his knees in between Dean’s bent legs. Sam presses a trail of soft, wet kisses down the crease of his hip, and Dean’s dick jumps to attention like it’s making up for lost time.

“Yup,” Dean says, voice a little too high. “Memory definitely jogged. Fantastic job.”

Sam chuckles into Dean’s skin and tilts his head to nuzzle at the base of Dean’s rapidly growing hard-on, fingernails biting into the sides of his thighs. “Well I _did_ promise,” he says, and then trails the tip of his tongue lightly up Dean’s shaft to circle the head, leaving a thin trace of moisture behind. It burns cold in the open air of the room, deliciously contradictory to the rest of Dean’s overheated skin. Sam presses a tender kiss to the very tip of Dean’s cock, and the unexpected chasteness of it sends a hot bolt of molten lust right through his core.

“So, you gonna quit with the virgin act sometime this century?” Dean asks roughly. “Or what?”

Sam responds by swallowing him down whole in one go, and Dean very quickly shuts the fuck up. He stifles a groan and tenses his thighs, stopping himself from immediately bucking up into the wet heat of Sam’s mouth. Sam lets out an amused sound at the slight hitching motions that Dean can’t help but make, and clasps his huge hands around Dean’s hips to hold him still while he sucks at him like a fucking Hoover. Dean bites down on his own tongue at Sam’s movements, a hint of pain to go with the sweet, languid ecstasy that his brother’s mouth is intent on providing, and spreads his legs so that Sam can press in even further. Which he does, because he's perfect and gorgeous and really fucking great at this. Dean takes a deep breath and reaches out to trail his fingers over Sam’s lips where they’re stretched wide and pink around the thickness of his cock, and then moves his hands back to tangle them in his brother's hair. Dean lets himself get lost in the wet slide of Sam’s throat, the way his eyes water involuntarily as he presses down again and again, stuffing himself full. Sam tightens his grip around Dean’s hips and yanks him closer, fingers brutally digging into the muscle, and Dean closes his fists in return, letting Sam feel the tug against his skull. He lets out a strangled sound as Sam pulls back just enough to twirl his tongue into the slit, and then Sam’s pulling off all the way, letting Dean’s dick slide from his lips with an obscene slurp.

“Why the fuck are you _stopping?”_ Dean gasps, fingers pulling at Sam’s head. “Keep going, man. I’ll get you back right afterwards.”

“I don’t think so,” Sam says, voice raspy and fucked-out. “You lost our bet, remember?”

Yes. Dean remembers. Of course he remembers. He had been desperately banking on the hope that _Sam_ wouldn’t remember. Dean groans miserably and slumps back onto the bed behind him. “Wouldn’t you rather have a blowjob?” he asks petulantly.

Sam laughs and slinks up over him, and Dean’s dick gives another aching twinge when Sam's abs slide up along the length of it. “No,” he says bluntly, dropping a quick kiss onto Dean’s lips. “Scoot back.”

Dean closes his eyes against the insistent throbbing of his swollen cock and then does as Sam asks, shoving himself backwards with a cranky sigh. “Real waste of a wish, man,” he says grumpily. “You could have had me be your library slave for a week or something.”

Sam slips himself into place underneath Dean, and runs his hands up his thighs. “Why does everything have to be such a fucking production with you?” he asks teasingly. “It’ll feel good, I promise.” Sam skims his fingertips back behind Dean’s balls to press around his rim, and Dean lets out an embarrassing whining noise at the fleeting contact. He’s still mostly open from the night before last, and his brother’s fingers slip in easily. Sam makes a sexy little gasping sound at the movement, and then grins up at him. “Okay, library slave,” he says, pleasantly insufferable. “Go get the lube.”

“Screw you,” Dean shoots back, and Sam laughs at the blatant disobedience, dimples cutting deep into the sides of his smile. And Dean loves it when Sam looks at him like that, so he gets up to go and get it anyway. He finds and grabs the little bottle of K-Y out of his duffle and chucks it at Sam’s head, but the little bitch manages to snag it out of the air one-handed. Because he’s an infuriating bastard. So Dean gives up, drags his feet back over to the bed, and leans down to hover above his brother, sweeping his gaze over the wonderfully pornographic display spread out beneath him.

Sam shifts a bit under Dean’s stare, and Dean’s eyes track the sinewy stretch of every muscle at the movement. Each cut and plane of Sam’s body is carved deeper and more distinct by the faint lamplight, and the view is so good that Dean’s starting not to care about the rest of it all. He glances back up to his brother’s face. Sam’s hair is mostly dry by now, lying dark and tangled across the white of the pillow underneath his head. It’s a tad coarser than usual, due to the seawater, and there are tiny flecks of lighter-colored sand speckled throughout the deeper brown. Dean smiles a little at the sight. Sam is gonna have one _hell_ of a rat’s nest come morning.

“C’mere,” Sam says, and then he tugs Dean down on top of him, barely letting him get settled before he’s snapping the cap on the lube and tipping the liquid out into Dean’s hand. “Get me ready,” he whispers.  

And Dean should balk at the order, but it’s unfairly hot and he can’t help but comply. He wraps his soaked hand around his brother’s straining cock and pulls, and Sam slams his eyes shut, throwing his head back with a low moan. “Yeah. That’s it, Sammy,” Dean purrs. “How’s that feel, baby?”

Sam lets Dean jack him for a minute, then makes another strangled noise and grabs at Dean’s waist. “C’mon,” he pants. “C’mon, Dean. Please.”

“Please what?” Dean asks smugly.

“Let me fuck you.” Sam tosses his head against the bed and bucks his hips up. “C’mon, Dean, let me fuck you.”

Dean gives Sam another couple of firm strokes, and then angles his dick the way Dean wants it, letting the head push against the rim of his hole. “This what you want, cowboy?” he whispers roughly. “Just like this?” Sam nods with a panting whine and digs his fingertips into Dean’s thighs. “Yeah, alright,” Dean says, and then he sinks all the way down, slowly impaling himself on Sam’s cock. And it feels fucking amazing, just like the rest of the times they’ve done it this way—but the open vulnerability of sitting over Sam like this is making him a little uneasy.

“C’mon, Dean. Ride me.” Sam wraps his hands around the cut of Dean’s hipbones and gazes up at him imploringly. “Ride me.”

Dean gives it his best effort, but it feels fucking weird. Like he’s a chick or something. His dick bounces embarrassingly as he pushes up on his thighs, and he lets himself drop back down into Sam’s lap. “This is ridiculous. I feel ridiculous.”

“You wanna turn around?” Sam asks, clearly struggling with forming the simple words.

“No,” he shoots back, way too quickly. “I am not reverse cowgirl-ing you.” Sam snorts a little and Dean pushes up again. His brother gasps at the tight slide, but he can’t quite get over the weirdness of the position. He feels oddly exposed like this, even more so than when Sam’s fucking him into some mattress, and it’s making him antsy. Dean shoves the insecure bullshit out of his head and rocks his hips faster, but that just makes his dick bounce even more and Dean growls as he clamps a hand around himself to keep it still.

He glances down at Sam to complain or something—maybe his brother will take pity on him and let them flip over—but all he sees is Sam biting at his lips and turning his face away so that he can laugh silently into the flat cotton of his pillow. Dean can’t hear anything, but the gleam of Sam’s grin catches the moonlight and he can feel his brother’s sides jumping between his thighs. “Are you fucking laughing at me?” he growls.

“No way, man,” Sam struggles out through clenched teeth, but the uneven dip in his voice gives him away entirely. “This is very serious and very sexy. I’m completely focused right now.”

“I cannot believe you’re fucking laughing at me.” Dean flicks his fingernail at the skin over Sam’s sternum. Hard. “I thought you wanted this.”

“I do,” Sam insists, flinching at Dean’s continued assault. “I just never thought that you’d actually do it,” he laughs. “ _Ow_ , dude! Stop it.”

It’s one thing to lose a bet, but the indignity of being laughed at during sex is something that Dean will not stand for—or sit for, whatever.

Sam lets out a plaintive, hurt sound as Dean slides up off his cock. “No,” he moans, fingers scrabbling at Dean’s retreating arms. “No. Where are you going? Come back. I’m sorry.  _Fuck_. Just come back.”

Dean ignores his brother’s pleas and awkwardly strides over to unzip Sam’s laptop bag. He slips the computer out of the scuffed leather casing, clunks it onto the nearby wicker table, and flips the thing open—bringing up Sam’s iTunes and clicking through to the playlist he’d made Sam create for him after he’d found that iPod at the thrift store in Boise.

“Dean, what the ever loving fuck are you doing?”

“You’re so happy with your stupid little bet, Sammy?” Dean tosses over his shoulder. “Fine. But I’m gonna get something out of this too.” He double clicks the trackpad, and then the high tones of Ian Anderson come blaring through the dinky speakers.

_“This is the story of the hare who lost his spectacles.”_

“No,” Sam gasps, eyes pleading. “Dean, no.”

He scoffs and crosses his arms over his chest. “Dean, _yes_.”

“At least—” Sam shoves himself up onto his elbows. “At least pick a different song, man. I’m _begging_ you.”

“You got something against rabbits, Sammy?”

“So…not sexy,” Sam says, grammar uncharacteristically disjointed as most of his blood is still clearly occupied elsewhere. “Least sexy thing you could possibly come up with.”

_“Owl loved to rest quietly whilst no one was watching.”_

“Jesus Christ, Dean.” Sam thumps his head back against the bed and throws his arm over his face. “Turn it off. I’m fucking begging you here.” His chest shakes as he lets out a stressed groan, and Dean gets a perfect view of Sam’s entire body outlined against the warm light—taut with need (and probably a fair amount of frustration), his cock glistening wet and blood-dark.

Dean swallows hard at the gorgeous tableau and turns back to the laptop, clicking on ‘Aqualung’ instead.

 _“Sitting on a park bench—”_ Anderson spits to the pounding guitar.

Sam lets out a sharp breath and props himself up on one elbow, raising an eyebrow as he meets Dean’s gaze. “Is this your best attempt at irony?” he asks tiredly.

“I could always go back to the first one,” Dean says.

“ _No!_  God, no.” Sam sits up all the way and reaches out for him. “Okay, fine. We can listen to your awful music. Just please come back.”

"I dunno, Sammy," Dean sing-songs. "I thought you hated Jethro Tull?"

"I do," Sam says exhaustedly. "They're the worst. Now come back here and let me fuck you."

Dean grins and swaggers back across the room, silently mouthing along to the lyrics.

_“Hey, Aqualung.”_

Sam groans again as Dean crawls back over him, hips hitching as Dean ducks his head to kiss along his brother’s jawline. “I hate it when you do that,” he says grudgingly. “It shouldn’t be allowed to be sexy.”

Dean smirks and scrapes his teeth over the vulnerable line of Sam’s throat. “You love it,” he says flippantly.

“Yeah,” Sam breathes, and then he stretches his hands out to clutch at Dean’s ass, crushing him down against his groin. “I want to do it like this,” he says desperately. “Fuck you like this. Please?”

“Yeah, Sammy,” he says quietly. Anderson hits his first bridge, the song shifts to something more melodic, and Dean leans down to suck at his brother's mouth. “Yeah, okay.” He falls back on one hand and lines them up again, Sam slipping in easier this time now that they’re both slicked. Sam’s brow scrunches up in tightly coiled pleasure and Dean ignores the self-consciousness crowding in around the edges of his thoughts, focusing instead on his brother, on how Sam looks like he’s just been given the world on a fucking plate. He wraps one hand around the back of Sam’s neck, braces the other against his chest, and leans forward just enough that he can fuck his ass back onto Sam’s cock, taking him as deep as he can. He works himself up and down, falling into an expert rhythm because Dean is fucking good at this, and then he's finally bottoming out on each thrust, Sam’s dick splitting him open so deep he doesn’t think he’ll ever be able to _not_ feel it.

Sam lets out a strained whine and clenches his hands tighter, slamming Dean hard into the cradle of his hips over and over again. “So hot, Dean,” he gasps, breathless and needy and maybe just a little too insightful for his own good. “The things you do to me. So fucking hot like this.”

Dean considers making a joke about being hot all of the time, but Sam tilts his hips with the next thrust and the blunt head of his dick starts ruthlessly pounding against Dean’s prostate and any concepts other than _hot wet deep Sam salt sweat_ _Sam fuck **Sam**_ —evaporate into thin air.

The laptop skips around his playlist a bit and Bad Company kicks on, which means Sam must have left it on shuffle, so Dean shifts the tempo, pitching his hips back to the beat of Rodgers’s whiskey smooth vocals.

Sam lets him set the pace for a short while, but then he braces his feet against the bed and starts rocking up to meet Dean on every go. Because the fucker has absolutely no sense of patience and can’t stand to be riding shotgun anywhere other than Baby. He brutally thrusts up until Dean’s legs start trembling, then slips out of the groove they’ve got going, faltering as his strokes get more and more reckless. Sam’s balls are heavy and tight when they press up against Dean’s ass, and his fingers are clenching and unclenching around his waist, and he’s close and Dean’s close too, so he reaches down to jack himself off for the big finish.  

Sam smacks his hand away. “No, don’t,” he pants. “Just like this. Please.”

“Sammy,” he groans, “I don’t know if—”

“You can, you can, you can,” Sam chants, practically drowning in his lust. He wrenches his hands up Dean’s sides to yank him down against his chest, arms squeezing tight across his back and hips bucking up shallowly where his cock is already seated deep. “C’mon, Dean,” he begs. “Just like this.”

Dean turns his face into Sam’s hair and breathes in the smell of sweat and brine. Sam’s still relentlessly punching at his prostate and Dean’s cock is trapped between the sinuous writhing of their bodies and he’s so fucking close—ready to pop off like a rocket. Sam opens his mouth against Dean’s neck, wet warmth of his tongue and a hint of teeth, and then Dean's coming, shooting hot and sticky where their chests are pressed together. Sam’s whole body jerks at the feel of Dean’s release, and he pulses inside of him in return—short nails scoring furrows into his shoulders as he rocks up into Dean one more time.

Dean lets Sam have the moment for a minute or two, resting spent and sated until their breathing starts edging back on normal, and then he makes a valiant attempt at untangling himself from his brother’s clingy limbs. Sam lets out an unhappy moan and wraps his arms even tighter. “No,” he mumbles. “Where are you going?”

Dean snorts and wriggles his shoulders under Sam’s unrelenting grip. “I’m fucking gross dude. I’m sticky and covered in spunk—” He tries to level his brother with a scathing look, but he can’t quite get his head free. “On both ends, so thanks so much for that,” he grumbles. “And you got your dirty ocean crap all over me.”

Sam laughs into his neck. “See? You should’ve waited to shower until after we fucked.”

“Well, maybe I’ll never fuck you again, you keep pawing at me like this.” Dean pulls hard and finally gets an arm loose. “How does that sound?”

“Sounds like the weakest, most unbelievable threat you’ve ever made,” Sam says flatly. “And that includes the time you swore you would never drink again after those dollar shots in Andalusia.”

“Whatever, dude. I was nineteen.” Dean digs his elbow into his brother’s side, and then Sam goes stiff—like actual _emotional_ stiff.

“Did you—?” Sam starts quietly, then he coughs and bites at his lip. “I mean, it wasn’t that bad, right?”

“We still talking about the Alabama Slammers?”

“I’m serious, Dean. I mean, this.” He waggles his hand. “It was okay?”

Dean drops a tender kiss to his brother’s cheekbone. “I came, didn’t I?”

“You’re fucking ridiculous, you know that?”

He throws Sam a shameless grin. “Yeah. But this ass is worth it.”

Sam just snorts incredulously and then shoves Dean out of the bed. And even though that had been Dean’s solitary goal for the last five minutes, he feels kind of affronted now that the decision was taken out of his hands. But if he reaches back for Sam, then the asshole will never let him hear the end of it, so he turns tail and makes his way back into the small bathroom. Dean grabs one of the tastefully arranged washcloths out of its seahorse-themed holder and goes to town over whatever areas of himself he can reach. The sticky, drying come is bad enough, but mostly he’s intent on getting the irritating squelch of lube out of his ass. It’s really the only major downside to letting his brother pitch. 

“Did you drown in there?” Sam calls out obnoxiously, from His Highness’s royal spot on the cushy bed while Dean is left dealing with all the clean-up.

“Fuck you too,” he replies sweetly, and then tosses the soiled washcloth into the corner with the rest of his heaped clothes. Now that his dick is no longer screaming for release, his other needs are making themselves known. Chief among them being the fact that he hasn’t eaten anything in over twenty-four hours. His stomach gurgles unhappily and Dean slaps at it with the flat of his palm as he saunters back into the main room. “God, I’m fucking hungry. Are you hungry? What time is it?” Dean slides Sam’s laptop over and shuts off Joe Elliott’s screech, then types a few words into the search bar. “Think they’ve got delivery up here?”

“Yes, Dean,” Sam says dryly. “I’m sure they’ve got delivery.” Then he flicks his eyes around the room and shifts a little awkwardly. “You sure you want company though?” he asks hesitantly. “Kinda smells like sex in here.”

“Smells like _ocean_ in here,” Dean tosses back, intentionally ignoring his brother’s ridiculous sense of modesty. “Just like the rest of the whole damn town.” He clicks on one of the pop-ups. “How does Chinese sound? I think I’m kinda off seafood for a while.”

Sam laughs condescendingly into his pillow. “When were you ever _on_ seafood?”

“Shut up, Sam. I eat seafood.” He squints as he thinks about it for a second, then victoriously proclaims, “Fish tacos!”

“Ah, yes,” Sam says. “The height of aquatic cuisine.”

“I’m gonna aquatic _your_ cuisine, you don’t shut your face.” Dean picks up his cell phone and punches in the number from the website. A hostess picks up immediately, and then chirps out a greeting and something else that seems like it could possibly be the name of the restaurant. He can’t quite make out what the woman on the line is saying _exactly_ —other than it sounding vaguely food related—but he figures she’ll be able to understand him fine if he sticks to their menu offerings. “Uh, yeah. Hi,” Dean says. “Can I get a plate of your Szechuan Beef? And one of the…” he pauses as he scans over the website menu. “One order of House Chow Mein.” He glances back to Sam. “You want your stupid make-believe meat?” His brother makes a quiet, grumbling noise, so Dean figures that’s a yes. “Yeah, with tofu.” Sam’s gonna sneak half of his beef anyway because he always does. The hostess makes an inquisitive sound that almost sounds like English. “Yup,” Dean says, guessing at the appropriate answer. “That’s it. Thanks.” He rattles off the motel’s address and the number from the closest credit card within grabbing distance, and then the woman makes a final, definitive noise, so Dean assumes that the conversation is over.

He tosses his phone onto the wicker table and then walks over to root through Sam’s backpack because it’s closer, pulling out a spare shirt and pair of boxers. “You planning on getting dressed before the poor delivery boy gets an eyeful?”

“Whatever,” Sam mumbles, settling in deeper under the comforter. “I’m under a blanket. It’s not like he’s coming inside.”

“Your choice,” Dean says, tugging the too-large v-neck over his head. “But don’t blame me when the poor guy catches a glimpse and has to stab his eyes out like what’s-his-face.” He waggles a hand around. “Oedipus.”

Sam snorts at the reference. “Was that an intentional incest joke?” he asks. “Or are you just being an ass?”

Dean shrugs. “Six of one…” He steps across to his side of the room, and then pauses as his eyes skim past the still-open website. “Eh, you know what? Fuck it.” Dean picks his phone back up from the table and hits redial, and that same unintelligible voice picks up again. “Hey,” he says. “I just left an order about three seconds ago.” He glances down at the credit card he’d just used. “Wilfred Mallard, that’s right. I wanted to see if there was any way I could add an order of Kung Pao Shrimp to my tab?” The voice pleasantly garbles an affirmative, and Dean flicks his eyes back to the giant outline of his brother. “And why don’t you toss in a couple of those Crab Rangoons too? My brother's on kind of a seafood kick.”

 

 

 

 

**Author's Note:**

> Title taken from Jimi Hendrix's "1983...(A Merman I Should Turn to Be)"


End file.
